후리그냥 낭탕 워 - maritexdownload.maritex.com.pl/pdfs/wi/trh03xm-cook.pdf · rfid system...

TRH03XM COOK BOOK

www.3ALogics.com |

COOKBOOK |

Scope This document contains information such as example circuit, guide, etc to help users to develop

HF (13.56MHz) RFID reader system more easily and conveniently.

(Reference system: 3ALogics Evaluation board – RSK100, RSK200L, RSK300)

Related 3ALogics Products TRH031M

TRH033M

Cookbook construction This Cookbook is divided by applications and provides actual test cases and examples with

theoretical explanations.

Application Access Control / Home Network & Digital Door Lock

POS Terminal / Public Transportation

Electronic Library / Intelligent Toys

E-Parking / Product Authentication

Distribution, Logistics

Confidential 1

TRH03XM COOK BOOK

2 ww.3ALogics.com Confidential | w

Revision history

Date Version Content

2008. 04. 11 0.1 Preliminary release

2008. 04. 16 1.0 1.0 version release

Notice : All referenced brands, product names, service name and trademarks are the property

of their respective owners.

AnyRead™ - is a trademark of 3ALogics.

Copyright © 2008 3ALogics Inc.

This draft document is a copyright-protected by 3ALogics. Except as permitted under the

applicable laws of the user’s country, neither this draft document nor any extract from it may

be reproduced, stored in a retrieval system or transmitted in any form or by any means,

electronic, photocopying, recording or otherwise, without prior written permission.

Disclaimer

3ALogics accepts no liability for the content

of this document, or for the consequences of

any actions taken on the basis of the

information provided, unless that information is

subsequently confirmed in writing. If you are

not the intended recipient you are notified that

disclosing, copying, distributing or taking any

action in reliance on the contents of this

information is strictly prohibited.

Contact 3ALogics Inc.

7th Fl., Hyundai-office Bldg., 9-4, Sunae-dong, Bundang-gu, Seongnam-si, Gyeonggi-do, 463-783 Korea TEL : (82)-(31)-715-7117 FAX : (82)-(31)-719-7551

Homepage: http://www.3ALogics.com

E-mail : [email protected]

Printed in the Republic of Korea.

http://www.3alogics.com/

mailto:[email protected]

TRH03XM COOK BOOK

www.3ALogics.com | Confidential 3

Document Contents

Chapter1 Concept of RFID and Reader IC Usage _________________________________ 7

1.1 RFID (Radio Frequency Identification) Concept ________________________________________________ 7

1.2 Reader IC (TRH03XM) Usage and Functions ___________________________________________________ 8

1) Usage __________________________________________________________________________________________ 8

2) Functions ______________________________________________________________________________________ 8

Chapter2 Reader System Configuration Using Atmel AT89C51ED2 _______________________________ 9

2.1 TRH03XM Interface _____________________________________________________________________________ 9

2.2 Clock Oscillator Related Circuit _________________________________________________________________ 9

2.3 TRH03XM and Microprocessor Interface ______________________________________________________ 10

1) Selecting Microprocessor Interface __________________________________________________________ 10

2) H/W Configuration by Interface Type ________________________________________________________ 11

3) H/W Configuration for SPI mode ____________________________________________________________ 12

2.4 Use Case of Atmel AT89C51ED2 ______________________________________________________________ 13

Chapter3 Designing HF Reader Antenna _______________________________________ 16

3.1 HF RFID System _______________________________________________________________________________ 16

3.2 Inductive Coupling RFID System Design Parameter ___________________________________________ 17

1) Magnetic field strength: H (A/m) ____________________________________________________________ 17

2) Couple Coefficient: k _________________________________________________________________________ 17

3) Resonance ____________________________________________________________________________________ 18

3.3 Antenna Design _______________________________________________________________________________ 18

3.4 Designed Antenna Radiation Pattern _________________________________________________________ 19

TRH03XM COOK BOOK


Chapter4 Antenna Matching Optimization and Application ___________________ 20

4.1 TRH03XM Antenna Matching Scope __________________________________________________________ 20

4.2 EMC Filter Impedance _________________________________________________________________________ 22

4.3 Directly Antenna Matching Method ___________________________________________________________ 23

1) Antenna Coil impedance measurement ______________________________________________________ 23

2) Antenna matching____________________________________________________________________________ 23

3) Antenna matching results ____________________________________________________________________ 24

4.4 EMC filter and matched antenna ______________________________________________________________ 25

4.5 Receiver Configuration ________________________________________________________________________ 26

4.6 Antenna and Q factor _________________________________________________________________________ 27

Chapter5 How to Design 50Ω Matching Circuit using Balun _______________________________ 28

5.1 Scope __________________________________________________________________________________________ 28

5.2 Balun and Antenna Circuit ____________________________________________________________________ 29

1) Balun Related Circuit _________________________________________________________________________ 29

2) Antenna Configuration _______________________________________________________________________ 30

5.3 Matching Process ______________________________________________________________________________ 30

5.4 Measurement __________________________________________________________________________________ 31

5.5 Gerber _________________________________________________________________________________________ 32

Chapter6 How to use TX Power Boost Up ______________________________________ 33

6.1 Power Boost Up _______________________________________________________________________________ 33

6.2 MOS Model Power Booster Design ___________________________________________________________ 34

1) MOS Model __________________________________________________________________________________ 34

2) DC Bias Circuit _______________________________________________________________________________ 35

3) Stability _______________________________________________________________________________________ 37

4) Input and Output Matching and Measurement _____________________________________________ 41

6.3 Power Booster Design Using S2P File _________________________________________________________ 44

1) S2P File Extract _______________________________________________________________________________ 44

2) Input/Output Matching and Measurement __________________________________________________ 45

TRH03XM COOK BOOK


Chapter7 EMC Problem Solving _________________________________________________ 47

7.1 EMC (Electromagnetic Compatibility) Scope __________________________________________________ 47

7.2 Electromagnetic Waves Radiation Standard ___________________________________________________ 48

7.3 EMI Noise Measure ____________________________________________________________________________ 48

1) Noise Measure Basis _________________________________________________________________________ 48

2) Noise Measure Technology __________________________________________________________________ 48

7.4 Reader System Design with EMI Noise Consideration ________________________________________ 49

1) System Noise Origination with TRH03XM ___________________________________________________ 49

2) Component Selection and Filtering __________________________________________________________ 49

3) Layout and Routing __________________________________________________________________________ 50

4) Shielding _____________________________________________________________________________________ 51

5) Other Considerations ________________________________________________________________________ 53

Chapter8 Air interface Measurement ___________________________________________ 54

8.1 Air interface ___________________________________________________________________________________ 54

8.2 Measurement __________________________________________________________________________________ 54

8.3 100% ASK Waveform __________________________________________________________________________ 55

1) ISO/IEC 14443A ______________________________________________________________________________ 55

2) ISO/IEC 15693 ________________________________________________________________________________ 56

8.4 10~30% ASK Waveform _______________________________________________________________________ 57

1) ISO/IEC 14443B ______________________________________________________________________________ 57

2) ISO/IEC 15693 ________________________________________________________________________________ 58

Chapter9 Modulation Index Control ____________________________________________ 59

9.1 Modulator Concept____________________________________________________________________________ 59

9.2 Modulator Index Adjustment __________________________________________________________________ 60

1) Standard Modulation Index __________________________________________________________________ 60

2) Modulation Index Control ____________________________________________________________________ 61

9.3 Adjustment Guide _____________________________________________________________________________ 63

TRH03XM COOK BOOK


Chapter10 Understanding Demodulation Actions ______________________________ 65

10.1 What is Demodulation? ______________________________________________________________________ 65

10.2 Demodulation Register _______________________________________________________________________ 66

10.3 Demodulation Signal Measurement _________________________________________________________ 68

1) Measurement Set up _________________________________________________________________________ 68

2) Measurement _________________________________________________________________________________ 69

Chapter11 Using Card detector _________________________________________________ 72

11.1 Card Detector Principle ______________________________________________________________________ 72

11.2 Card Detector Application ___________________________________________________________________ 72

11.3 Card Detector Movement ____________________________________________________________________ 73

1) Card Detector Basic Movement ______________________________________________________________ 73

2) Card Detector Register Map _________________________________________________________________ 73

11.4 Card Detector Set-up Procedure _____________________________________________________________ 74

11.5 Practical Application _________________________________________________________________________ 75

TRH03XM COOK BOOK

www.3ALogics.com |

Chapter1 Concept of RFID and Reader IC

Usage

1.1 RFID (Radio Frequency Identification) Concept

RFID is an automatic identification technology using air interface to retrieve data from tags.

Concept of reading tag information is similar to reading barcode. However, reader does not

need to be so close to the tag to read data. Some tags can be read from several meters away

and beyond the line of sight of the reader. Also multiple tags can be read simultaneously so

application area is very broad.

RFID system comprise of reader, antenna, tag, server and network. As seen on below Picture

1-1, PC sends command to reader to read signal, then through antenna, tag signal is transmitted

to reader. This data is converted to recognizable form and sent to PC.

Below Picture 1-1 displays RFID system implementation.

ModulationMagnetic field

TransmitterControl

&Analysis

Confidential 7

Receiver

TAGIC

Demodulation

Picture 1-1 RFID System Implementation

TRH03XM COOK BOOK


1.2 Reader IC (TRH03XM) Usage and Functions

1) Usage

13.56MHz RFID reader system is left block of Picture 1-1. Microprocessor is a controller for

analysis function. 3ALogics reader IC will perform the roll transmitter and receiver. Reader IC

receives command and data from microprocessor and converts signal to meet each protocol

specifications. This signal is transferred to tag through antenna. Receiving process is in reverse

of previous process. Received data is converted to digital data by Reader IC and stored in FIFO.

Afterwards, microprocessor takes data received through reader IC. Basically microprocessor

communicates with tag through reader IC, thus, reader IC provides air interface communication

capability.

2) Functions

- Modulation / Demodulation

- Encoding / Decoding

- Framing

- Data integrity

- Timer and interrupt

(Refer to: TRH031M Data sheet)

TRH03XM COOK BOOK

www.3ALogics.com |

Chapter2 Reader System Configuration Using Atmel

AT89C51ED2

2.1 TRH03XM Interface

TRH03XM do not embed microprocessor thus TRH03XM must be controlled by separate

microprocessor. Therefore, user must configure interface with microprocessor to function

TRH03XM. This chapter explains interface between microprocessor and TRH03XM (except RF

interface) and related circuit configurations.

2.2 Clock Oscillator Related Circuit

Very basic circuit to function TRH03XM is Clock Oscillator. Circuit using Crystal Oscillator to

operate TRH03XM is described in below picture. This circuit, unlike ordinary circuits, connected

with 1MΩ resistor in parallel with Crystal Oscillator.

Picture 2-1 Clock Oscillator Related Circuit

Confidential 9

TRH03XM COOK BOOK


2.3 TRH03XM and Microprocessor Interface

1) Selecting Microprocessor Interface

TRH03XM supports 5 types of microprocessor interface. Therefore, user must select what

interface will be used prior to configuring TRH03XM hardware. First thing to be considered in

selecting interface is availability of ports quantity for microprocessor and TRH03XM interface.

Chart 2-1 Number of Ports by Interface

Interface Type Number of Ports Parallel/Serial

SPI 5 Serial

Separated Multiplexed 13 Parallel

Common Multiplexed 13 Parallel

Separated Dedicated 15 Parallel

Common Dedicated 15 Parallel

Next is communication speed. SPI mode is slower than other available interfaces.

Each interface has both advantages and disadvantages. However, 3ALogics recommends

Separated Multiplexed mode if enough ports are available, and SPI is recommended if minimum

quantity of ports is needed.

TRH03XM COOK BOOK

www.3ALogics.com |

2) H/W Configuration by Interface Type

After selecting interface type next step is to configure hardware to fit that type. Whether to

select Separated mode or Common mode is determined by software thus user only need to

configure hardware if using Multiplexed mode and Dedicated mode. Also hardware can be

configured to select Multiplexed mode and Dedicated mode by software.

Picture 2-2 displays hardware configuration method by interface type. For Multiplexed mode,

ADDR2, ADDR1, and ADDR0 are assigned High, High, and Low value. However, this is just an

example and user can select each value. However, using Dedicated mode, PALE value must have

High value.

Picture 2-2 Hardware Configuration Method by Interface Mode

Confidential 11

TRH03XM COOK BOOK

3) H/W Configuration for SPI mode

Picture 2-3 displays hardware configuration using SPI mode. When SPI is embedded in

microprocessor connect circuits corresponding to each port name (NSS, MOSI, SCK, and MISO).

If SPI is not embedded in microprocessor then select arbitrary port to connect NSS, MOSI, SCK,

and MISO and operate using software. From the picture each High/Low value assigned to each

port cannot be changed by user. TRH03XM SPI communication will not function if wrong

High/Low value is entered.

Picture 2-3 H/W Configuration Method Using SPI Mode


TRH03XM COOK BOOK

www.3ALogics.com |

2.4 Use Case of Atmel AT89C51ED2

Based on information provided in previous chapter, here is a use case using 3ALogics RSK

board. (Reference: RSK100, RSK200L, and RSK300)

(a) Schematic

Dedicated/Multiplexed

Address mode

Confidential 13

RDB

PALE

CSB

WRB

DATA0~7

ADDR0~2

RSTP0.7/AD7

P0.6/AD6

P0.5/AD5

P0.4/AD4

P0.3/AD3

P0.2~0/AD2~0

P1.0~P1.7

(b) Interface Configuration

Picture 2-4 AT89C51ED2 Related Circuit Configuration (RSK board)

TRH03XM COOK BOOK

Atmel’s AT89C51ED2 is used for μ-Processor. TRH03XM chip and MCU interface are configured

to select Multiplexed mode and Dedicated mode using software (Picture 2-4). Total of 4 ports (8

bit port: P0, P1, P2, P3); P0 controls TRH03XM, P1 is TRH03XM data port, P2 controls LCD, and P3

is allocated for interrupt and RS232 communication port. AT89C51ED2 has 64K byte flash ROM

and 256byte RAM so programming is possible. For programming mode selection, PSEN is the

circuit to handle process. POR (Power On Reset) circuit for chip initial reset, Crystal Oscillator for

system clock, and RS232 circuit for RS232 communication. Circuits for LCD control and

configuration are for RSK board application only. They are optional circuits for hardware

configuration and not required for other RFID application development.

Picture 2-5 TRH03XM Related Circuit Configuration (RSK board)

TRH03XM is configured to 3 power source (AVDD, DVDD, and TVDD) for reliable supply of

power and to avoid Analog/Digital electric noise interference. AVDD is Receiver power. DVDD is

Digital power, and TVDD is Transmitter power. Circuit should be designed separating power as

seen on Picture 2-5.

However for ground, since substrate is not separated from chip internally, should be designed

to share AVSS, DVSS, and TVSS externally.


At this point basic circuits are configured to control TRH03XM, and Analog part remains that is

TRH03XM COOK BOOK


key feature of RF Transceiver. Transmitter comprises of EMC filter layer (Converts square wave to

Analog sine wave), matching layer configured between Antenna and filter layer, and Antenna.

Receiver comprises of attenuator resistor (to send high voltage signal from antenna to chip

inner part) and circuit for DC offset re-modulation. Detailed information is available in Chapter 3

and 4.

TRH03XM COOK BOOK

Chapter3 Designing HF Reader Antenna

3.1 HF RFID System

RFID systems work largely based on inductive coupling theory. Therefore, to understand

electric power and data communication, user should understand magnetic field and electric

theory. Less than 30MHz RFID applications, inductive coupling is used for data transmitting and

receiving. For above 30MHz, data transmitting and receiving are based on electromagnetic

waves. Antenna design method, power calculation and theory are similar to standard RF

communication. It’s easy to get confused with HF Antenna and power calculation. Picture 3-1

displays inductive coupling scope diagram. It performs like transformer in electronic circuit.

Picture 3-1 Inductive Coupling


TRH03XM COOK BOOK

www.3ALogics.com |

3.2 Inductive Coupling RFID System Design Parameter

1) Magnetic field strength: H (A/m)

This is an index to determine near field strength forms around coil when electric current is sent

from coil antenna. In HF RFID system it is transmission output.

Definition for strength in each ISO standard is as below.

- ISO/IEC 14443: 1.5A/m rms ~ 7.5A/m rms

- ISO/IEC 15693: 150mA/m rms ~ 5A/m rms

Simply, user can calculate magnetic field strength from point X (Rectangular conductor loop:

Length (a) X Width (b)) using below formula.

Confidential 17

⎟⎟⎟⎟

⎠

⎞

⎜⎜⎜⎜

⎝

⎛

++

+⋅

++

⋅⋅=

2222222 )2

(

1

)2

(

1

)2

()2

(4 xbxaxba

abINHπ

Through above formula, user can find out number of windings (N) and current (I). (N) and (I)

are in proportion to (H).

2) Couple Coefficient: k

Mutual inductance is a quantitative description of the flux coupling of two conductor loops. The

coupling coefficient k is introduced so that we can make a qualitative prediction about the

coupling of the conductor loops independent of their geometric dimensions.

21 LLMk⋅

= M: Mutual inductance

TRH03XM COOK BOOK

Coupling coefficient changes from 0 and 1. 1 means coupling and 0 means not coupled.

From below formula, if either one antenna is smaller than the other, coupling coefficient becomes

smaller.

.

readerTag rr ≤ / ( )322

22

readerreaderTag

readerTag

rxrr

rrk

+⋅⋅

⋅≈


readerTag rr ≥ / ( )322

22

TagreaderTag

readerTag

rxrr

rrk

+⋅⋅

⋅≈

Contactless smart card is produced in ID-1 size standard. Considering above coupling

coefficient, produce reader system antenna in ID-1 size as default size. Since couple coefficient is

high user can expect improved reading distance. In case of designing non-standard ID-1 size

antenna (bigger or smaller), 3ALogics recommends antenna size to be within 0.5x or 1.5x of ID-1

size.

3) Resonance

Reader and Tag antenna resonance frequency should be 13.56MHz, but there is a variance of

about 1~5MHz for multiple cards anti-collision reading. The reason for this variance is multiple

tags affects reduction of resonance frequency. Also it could be due to dielectric constant by

human hands.

(Reference: Reader Resonance – Chapter 4)

3.3 Antenna Design

Loop antenna is comprised of conductive material in coil shape. Antenna size with coupling

coefficient consideration is already mentioned in above. Most misunderstood part of antenna

design is in coil length. In UHF, antenna length should be 1/2 of wavelength (λ), but for HF,

using same formula then antenna coil must be 11m. Thus, this is not a proper way. Based on

numerous design experiences, 3ALogics recommends coil winding numbers should be optimized

to have 1μH ~ 2μH inductance variance for optimum performance.

TRH03XM COOK BOOK

www.3ALogics.com |

3.4 Designed Antenna Radiation Pattern

If antenna physical dimension is determined, antenna simulation is necessary. However,

antenna is similar to standard ID-1 size and inductance is same as above mentioned, actual

antenna performance will be stable without simulation process. This document does not provide

explanation on simulation. This document provides examples radiation pattern of simulation

result. Picture 3-2 is antenna coil pattern before simulation. It uses Zeland’s IE3D antenna

simulation tool.

Picture 3-2 Coil Antenna

Picture 3-3 is Coil Antenna radiation pattern.

Confidential 19

Picture 3-3 Coil Antenna Radiation Pattern

TRH03XM COOK BOOK

Chapter4 Antenna Matching Optimization

and Application

4.1 TRH03XM Antenna Matching Scope

TRH03XM transmitter/receiver layer analog off-chip basic configuration is as below Picture 4-1.

Transmitter comprises of EMC filter (that converts square wave to sine wave and simultaneously

amplifies analog signal and eliminating high frequency noise, antenna, matching layer, and

antenna coil. Receiver comprises blocks of attenuator (adjusts data received through antenna to

chip input dynamic voltage range(≤ 3.6Vpk-pk)), and high pass filter (eliminating dc offset and re-

adjust half VDD(VMID) offset voltage).

R2


Picture 4-1 Analog Off-chip Component

TRH03XM COOK BOOK

www.3ALogics.com |

Picture 4-2 displays Transmitter related equivalent circuit using Zload. Load 15Ω is optimum

impedance value for TRH03XM minimum noise, maximum gain, and maximum output power.

Transmitter Zload should not exceed 15Ω when designing.

Picture 4-2 TRH03XM Optimum Load Impedance

For HF RFID applications, direct matching is preferred over of 50Ω impedance matching for

ordinary RF system coil antenna.

(Reference: Chapter 5 covers 50Ω matching method using RF coaxial cable and Balun device.)

Confidential 21

TRH03XM COOK BOOK

4.2 EMC Filter Impedance

Picture 4-3 displays Zload conversion process by EMC filter. Impedance conversion occurs by L0a

from 1 to 2 and C0a from 2 to 3. For antenna applied to next layer by EMC filter impedance

value should be matched with 500Ω.

- 1: 15Ω, 2: 15 + j85 3: 500Ω

(a) TRH03XM and EMC filter impedance (b) Smith Chart

Picture 4-3 Impedance Transition (By EMC filter / 15Ω from 500Ω to)

EMC filter is LC type low-pass filter that is designed with 13.56MHz resonance frequency (fres).

For example when EMC filter series inductor value is 1μH, parallel capacitor value is 136pF, and

when series inductor value is 2.2μH then parallel capacitor value should be 47pF.

LCfres π2

1=

EMC filter is critical for high frequency noise elimination. Coil type having high Q is ideal for

inductor.


TRH03XM COOK BOOK

www.3ALogics.com |

4.3 Directly Antenna Matching Method

1) Antenna Coil impedance measurement

To match HF loop antenna first user must measure inductance (L) and resistance (R) value of

antenna. L and R value can be measured using Network Analyzer and to minimize TX1 and TX2

coupling error, connect TX1+TX2 instead of TX1+GND and TX2+GND to measure. (See Picture 4-

4)

Network Analyzer EX) Agilent / 8753ES

Picture 4-4 Antenna Impedance Measurement

2) Antenna matching

Measured value are L/2 = Lanta = Lantb, R/2 = Ranta = Rantb. As seen on Picture 4-5, antenna

should be equivalent. C2a, C2b and antenna coil (Lanta, Lantb) are resonant. EMC filter is

connected to C1a and C1b. (C1a, C1b: 15pF ~ 47pF)

Confidential 23

Picture 4-5 Antenna matching schematic

TRH03XM COOK BOOK

Ranta and Rantb determine antenna Q factor and value is higher than Q value is lower and if

value is lower than Q value becomes high. (Reference: 4-5 Antenna and Q factor)

Picture 4-6 Smith-chart Antenna Matching

Picture 4-6 is process of antenna matching to 500Ω in Smith-chart. Impedance changes to 500

Ω by parallel capacitor C2 to point 2 and series capacitor C1 to point 3.

3) Antenna matching results

Measuring TX1+GND using Network Analyzer after antenna matching displays result (Picture 4-7)

to 500Ω.

Picture 4-7 TX1 Measure Result after Antenna Matching


TRH03XM COOK BOOK

www.3ALogics.com |

4.4 EMC filter and matched antenna

After antenna 500Ω matching is complete, combine EMC filter and matched antenna to tune C2a.

Finally, tuning is to find a point where reading distance is the highest point by moving tag into

the antenna and should be kept within ± 10pF. Picture 4-8 displays measure point after final

tuning.

Picture 4-8 EMC Filter & Matched Antenna Measure Point

Picture 4-9 displays measure result that optimum impedance value is Zload≤15Ω.

Confidential 25

Picture 4-9 EMC Filter and Matched Antenna Measure Result

TRH03XM COOK BOOK

4.5 Receiver Configuration

Receiver is simpler configuration compared to transmitter. Refer to Picture 4-10 below.

Receiving signal from antenna and through R1, signal is reduced. By C3, R2 and R3 re-adjust DC

offset to adjust chip internal voltage as well as reduce voltage. C4 is bypass capacitor to stabilize

VMID voltage and functions as VMID voltage medium value of plus and minus in internal chip

function.

Picture 4-10 Receiver Schematic

C3, R3 and C4 should be 1nF, 820Ω and 100nF accordingly. R1 and R2 are flexible based on

each system board. RX input dynamic voltage range is ≤ 3.6Vpk-pk and will operate even with

weak voltage input. However, for receiving efficiency RX input should be high. Considering

receiving efficiency and tag reading percentage, minimum entry should be 2.7Vpk-pk, and 3ALogics

recommends RX input signal to be adjusted to 3.0~3.3Vpk-pk.


TRH03XM COOK BOOK

www.3ALogics.com |

4.6 Antenna and Q factor

From HF reader antenna C1a, C1b, Rexta, Rextb, Ranta and Rantb determine Q factor. Basically Q

factor is adjusted through C1a and C1b, thus, Rexta and Rextb use 0Ω. When Q factor value is

high, high power is delivered, but when bandwidth is reduced, bit rate error can occur.

Conversely, when Q factor value is small, bandwidth will increase but delivered power is reduced,

thus, tag reading distance can be reduced. Therefore, finding optimum Q value for antenna

matching process is very important.

Picture 4-11 Antenna Q Factor

Below Chart 4-1 displays relationship between C1a/C1b and Q factor and Ranta/Rantb and Q

factor.

Chart 4-1 Q factor, Band Width & C1, Rant

C1a, C1b ↑ ↓ Ranta, Rantb ↑ ↓

BW ↓ ↑ BW ↑ ↓

Q ↑ ↓ Q ↓ ↑

Confidential 27

TRH03XM COOK BOOK

Chapter5 How to Design 50Ω Matching Circuit using

Balun

5.1 Scope

HF RFID tag using 13.56MHz frequency energy source is RF system electric field not

electromagnetic waves. Antenna capability is determined by how well electric field energy source

allows current flow to run smoothly for energy transfer efficiency. For Ordinary HF RFID system

antenna matching uses direct matching method. Not like RF system generating electromagnetic

waves, frequency is low and current is transferred to antenna coil to generate electric field.

However, distance between system and antenna is lengthened, there could be some damages.

This document separates directly matching and 50Ω matching by 13.56MHz frequency

wavelength (λ=22m) 1/10th value (approximately 1m).

(Reference: 3ALogics Product RFLEV01)

(a) Direct Antenna Matching

(b) 50ohm Matching


Picture 5-1 Antenna Matching Summary Chart

TRH03XM COOK BOOK


.2 Balun and Antenna Circuit

1) Balun Related Circuit

alun used in HF antenna matching is coil type transformer that converts Balanced input(TX1,

T

5

B

X2) to Unbalanced output(1port antenna). It converts differential analog signal to single ended

analog signal and supply voltage to antenna through RF cable. Therefore, when system board

(RF module) and Antenna are apart, they can be connected using RF cable. Picture 5-2 is Balun

related circuit. It connects analog differential signal (EMC filter output) and receiver circuit and

for final layer configuration, SMA for RF cable connection.

(a) RF Modul (Analog off-chip) e

(b) Balun Circuit

Picture 5-2 Balun Related Circuit

TRH03XM COOK BOOK

2) Antenna Configuration

Picture 5-3 displays antenna circuit comprises of series capacitor for analog signal connection

and matching and parallel capacitor for resonance.

Picture 5-3 50Ω Matching Antenna Schematic

5.3 Matching Process

#3 and #5 pin are TX1 and TX2 (From Picture 5-2). When measured using Network Analyzer,

tune C15, C17, C13, and C14 to be 50Ω as seen below Picture 5-4.


Picture 5-4 50Ω Matching Process

TRH03XM COOK BOOK

www.3ALogics.com |

5.4 Measurement

Picture 5-5 displays measurement using Network Analyzer. User can confirm TX1 and TX2 are

matched to 50Ω.

Picture 5-5 TX1, TX2 Measurement

Picture 5-7 displays TX1 and TX2 exact summation through Balun.

(a) 50ohm Matching Antenna (b) Direct Matching Antenna

Picture 5-6 Analog Signal Measured through Antenna

Confidential 31

TRH03XM COOK BOOK

5.5 Gerber

(a) 50Ω Matching Antenna

(b) Balun Circuit

Picture 5-7 50Ω Matching Circuit Gerber


TRH03XM COOK BOOK

www.3ALogics.com |

Chapter6 How to use TX Power Boost Up

6.1 Power Boost Up

Transmitter power boost up is not a necessary application for contactless smartcard standards

such as ISO/IEC 14443 and 15693. For security measurement contactless smartcard limits reading

distance. However extending RFID application to ISO/IEC 18000-3, meaning changes. ISO/IEC

15693 standard use ISO/IEC 18000-3 thus supports long range mode. Therefore, for long range

reading distance using ISO/IEC 15693 protocol, need to amplify transmitter output. As displayed

in Picture 6-1, power boost up configures system using external AMP layer. Also larger antenna

is used compared to standard card size antenna.

Picture 6-1 Power boost-up Chart (3ALogics RSK 200L)

Power boost up design covered in this page is same as RF power amplifier design using NMOS

amplifier (NXP: BLF245). Before setting devices on PCB board, circuit and device level simulation is

necessary. Important point from this simulation is devices signifying DC and AC characteristics

parameter. Next point to be covered is design method of most important active device, MOS,

parameter characteristics.

Confidential 33

TRH03XM COOK BOOK

6.2 MOS Model Power Booster Design

1) MOS Model

To design Power booster, user must select MOS in consideration with temperature, operating

frequency, gain, etc. After selecting MOS, there are two ways; designing model with given

reference design and designing using S2P file. This document explains designing using ADS

(Advance Design System) tool. Instead of designing MOS modeling, import spice model offered

with RSK evaluation kit. MOS model imported to ADS is as follows in Picture 6-2.


Picture 6-2 Imported MOS Model

TRH03XM COOK BOOK

www.3ALogics.com |

To check if accurate model is imported compare I-V curve characteristics in MOS datasheet

through I-V curve tracer. As in Picture 6-3, user can confirm I-V curve characteristics are similar

or equal to simulation.

Picture 6-3 I-V Curve Characteristics Comparison (Simulation & Datasheet)

2) DC Bias Circuit

DC bias points are different by designed device usage. As in Picture 6-4, select optimum power

booster point by higher output power & higher efficiency.

Confidential 35

Picture 6-4 DC Bias Point

TRH03XM COOK BOOK

Use high capacity DC block capacitor (Ideal) for input and output, and DC feed inductor (Ideal)

for bias layer. Also as seen on Picture 6-5, DC bias circuit such as voltage divider.

Picture 6-5 Bias Circuit


TRH03XM COOK BOOK

www.3ALogics.com |

3) Stability

To maximize power booster output for maximum power gain from MOS, Simultaneous

Conjugate Matching design is necessary. For Simultaneous Conjugate matching MOS

unconditional stability is a must. Stability can be predicted using MOS S-parameter, and

parameter for MOS stability prediction is K factor.

22112

2222

211

2

1

SS

SSK

Δ+−−=

21122211 SSSSΔ = −

K>1 is unconditional stability, and K<1 is conditional stability. Picture 6-6 displays stable region

from each condition.

(a) Conditional Stability Area (K<1)

(b) Unconditional Stability Area (K>1)

Confidential 37

Picture 6-6 Stability

TRH03XM COOK BOOK

If specific frequency escapes stable region, becomes ΙΓinΙ>1, ΙΓoutΙ>1, thus, power booster

oscillates. For oscillation removing method there are; using resistor in transmitter/receiver

(Picture 6-7), using source feedback inductor, using bias capacitor, and use gate-drain feedback.


in

out

in

out

in

out

in

out

Picture 6-7 Removing Oscillation Using Input/Output Resistor

When using input resistor, matching performance is improved and oscillation is removed easily

but noise characteristics becomes worse, thus, not often used for circuit design with importance

in noise characteristics such as LNA (Low Noise Amplifier). When using output resistor, Linearity

is improved and oscillation is removed but loss in power output occurs, thus, not recommended

for power amplifier. Using source feedback (Picture 6-8) method picks up impedance matching

in all areas and seizes oscillation reducing AC elements from gate-drain feedback.

Picture 6-8 Removing Oscillation using Source, Gate-Drain Feedback

TRH03XM COOK BOOK

www.3ALogics.com |

Based on above oscillation removing method, stability circuit is configured using input resistor in

power booster circuit and bypass capacitor in DC bias.

Picture 6-9 Stability Circuit

Confidential 39

TRH03XM COOK BOOK

From the result (Picture 6-10) user can confirm unconditional stability region.

(a) Stability (Before Removing Oscillation)

(b) Stability (After Removing Oscillation)


Picture 6-10 Power Booster Circuit Stability

TRH03XM COOK BOOK

www.3ALogics.com |

4) Input and Output Matching and Measurement

For input/output matching, user must determine using of conjugate matching (both

input/output), not conjugate matching (output only) or load-pull. All these are to enhance

stability. Next explanation will be about power booster matching is input/output conjugated

matching method. Picture 6-11 is a circuit for input matching.

Picture 6-11 Input Matching Circuit Picture 6-12 is result of input matching. Approximately setting at 50Ω, through input/output

matching tuning to 50Ω matching.

Confidential 41

Picture 6-12 Simulation Result after Input Matching

TRH03XM COOK BOOK

Picture 6-13 is output matching circuit configured with DC block and T-matching.

Picture 6-13 Output Matching Circuit

After Input/output matching, input/output conjugate matching result is seen as Picture 6-14.


Picture 6-14 Simulation Result after Input/Output Matching

TRH03XM COOK BOOK

www.3ALogics.com |

Up to this point, simulation was done using ideal components but should go through new

tuning process using actual component that will be used. Power booster final measure result

after tuning process is as seen on Picture 6-15.

Confidential 43

Picture 6-15 Power Booster Measurement Result

TRH03XM COOK BOOK

6.3 Power Booster Design Using S2P File

1) S2P File Extract

To design power booster using S2P file, first obtain S2P file from MOS manufacturer and create

same bias circuit then go through simulation. Or, create bias circuit then extract S2P file.

Picture 6-16 displays S2P file extracting steps using Network Analyzer.

Picture 6-16 S2P File Extracting Steps

Picture 6-17 displays parts of extracted S2P file format through above process.


Picture 6-17 Extracted S2P File

TRH03XM COOK BOOK

www.3ALogics.com |

2) Input/Output Matching and Measurement

When designing power booster using S2P file, bias circuit is not necessary since bias information

is included in S2P file. Picture 6-18 displays stabilization process and status after input/output

matching.

Picture 6-18 Input/Output Matching Circuit

Picture 6-19 displays simulation result using actual component.

Confidential 45

Picture 6-19 Simulation Result after Input/Output Matching

TRH03XM COOK BOOK

Picture 6-20 is final measurement result after power booster configuration. Actual simulation

may not be exactly the same.

Picture 6-20 Power Booster Measurement Result


(Reference: Above mentioned power booster circuit, actual board and system can be confirmed

using RSK200L evaluation kit.)

TRH03XM COOK BOOK

www.3ALogics.com |

Chapter7 EMC Problem Solving

7.1 EMC (Electromagnetic Compatibility) Scope

EMC is capability to co-exist in electromagnetic waves environment with acceptable performance

without signal data loss as well as not impacting electromagnetic waves disorder to surrounding

environment.

Picture 7-1 EMC Classification

EMC classification is as seen on above Picture 7-1. For actual certification testing process EMI

Test classified as intra-system EMC. Not only for EMI but also for application area specification

and measuring elements are different. Major measuring element, EMI

(Electromagnetic Interference), is divided into CE/RE (Conducted/Radiated Emission) and

CS/RS(Conducted /Radiated Susceptibility) that electromagnetic waves can inflict system

erformance reduction.

- DM: Differential-Mode Interference

p

Confidential 47

- CM: Common-Mode Interference

TRH03XM COOK BOOK


.2 Electromagnetic Waves Radiation Standard

standards are different. Below

art lists electromagnetic waves allowance by Class A and B.

: For exact standard please check electromagnetic waves limitation standards from each

untry)

Chart 7-1 Electromagnetic aves Radiation Standard

7

By each country and region electromagnetic waves radiation

ch

(Reference

co

W

Classification Measure Dist (m) Frequency (MHz) Allowance (dBµV/m)

A class 10m 230 ~ 1,000 47

20 ~ 230 40

B class 10m 230 ~ 1,000 37

20 ~ 230 30

7.3 EMI Noise Measure

1) Noise Measure Basis

se by configuring circuit to control noise cause

nd transfer factor and eliminating mixed in noise.

2) Noise Measure Technology

ed when designing circuit. Basic technology is PCB design and

circuit design for noise isolation.

Basic three noise measures are; ‘do not create noise’, ‘do not transfer noise’ and ‘do not respond

to noise’. Basically noise measure is to remove noi

a

If user knows noise source, removing method is not so difficult. However, basic noise control

design technology must be appli

TRH03XM COOK BOOK

www.3ALogics.com |

For EMI noise control technology methods are in Picture 7-2 below.

TIME COST

Control

Technology

Selecting At Initial Design Low Cost

Layout

Routing

Impedance matching

Isolation

Grounding

Filtering

Shielding Possible to append Expensive

Picture 7-2 EMI Noise Measure Technology Type

7.4 Reader System Design with EMI Noise Consideration

1) System Noise Origination with TRH03XM

TX1 and TX2 are signal ports with highest operating capacity in TRH03XM chip and output

square wave. Square wave signal includes original frequency and high frequency noise. Crystal

oscillator and MCU interface data line also create noise but TX1 and TX2 ports are the most

potential noise creating reason.

2) Component Selection and Filtering

TX1 and TX2 signals should be filtered and converted to analog signal before sending to

antenna. At this point most important factor is Q value of EMC filter. Based on this value, high

frequency noise can be controlled.

- L = 1μH (TDK NL322522T – 1R0J / Q =30)

- C = 68pF (Tolerance ≤ 2%)

Inductor in EMC filter is recommended to use high Q wire wound inductor and low tolerance

capacitor.

Confidential 49

TRH03XM COOK BOOK

RX

TX1

TX2

VMID

1uH

1uH

68pF 68pF

68pF 68pF

15pF

15pF

120pF

120pF

39pF

39pF

0

0

0

0

3.0k

820

100nF

1nF1.0k

Picture 7-3 Analog Off-chip Component (RSK board)

3) Layout and Routing

- Arrange TX1/TX2 pin and inductor in EMC filter as close as possible

- Avoid via hole where transmission line pass through analog signal.

- Layout TX1 and TX2 symmetrically

(a) (b) (c)

Picture 7-4 Transmitter Off-chip Placement Example

Picture 7-4 (a) displays using via hole in signal line (Not recommended), (b) displays EMC filter

away with ferrite chip inductor with bad Q value, and (c) displays correctly designed Transmitter.


TRH03XM COOK BOOK

www.3ALogics.com |

4) Shielding

By inserting ground line between signals it reduces high voltage transmission signal

interference and receiver signal interference.

GND

GND

GND

GND

TX2/ANT2

TX1/ANT1

RX_in

GND

GND

GND

TX2/ANT2

TX1/ANT1

RX_in

TX2/ANT2

TX1/ANT1

RX_in

(a) (b) (c)

Picture 7-5 Antenna Connection Example

As seen in Picture 7-5, when inserting ground signal between signal lines as (a) and (b), signal

extension and ground shielding for wiring will automatically occur. (c) is not recommended.

Below Picture 7-6 displays antenna coil and ground shield pattern. Antenna connector and

matching circuits should be as close as possible. To reduce electric field insert ground shielding

patter (Picture 7-6) is inserted.

Confidential 51

Picture 7-6 Antenna Coil and Ground Shield Pattern

TRH03XM COOK BOOK

Antenna should use more than 2 layer board and to minimize EMI noise and electrical field use

4 layer board. Picture 7-7 displays RSK board antenna Gerber using 2 layer board. It is

optimized antenna pattern with coil and signal line (TOP) and shield pattern (BOTTOM).

(Card size: ID1 size, ISO/IEC 7810)

(a) TOP layer

(b) Bottom layer

Picture 7-7 Card Size Antenna Coil Gerber Example (2 Layer)


TRH03XM COOK BOOK

www.3ALogics.com |

5) Other Considerations

If EMI noise measure is executed as guided on previous chapter, noise from Reader IC will be

under control. For example Picture 7-8, displays improved performance of EMC filter inductor

replacing ferrite chip inductor to high Q value wire wound inductor.

(a) Above Standard Noise (b) Below Standard Noise

Picture 7-8 EMI Noise Examples

When noise spacing is 13.56MHz, user can assume the noise is from Reader IC transmitter.

Other noise can be predicted that it comes from MCU interface line or power source. Place EMI

device to suspicious interface I/O or power source, or using 4 layer to strengthen shield pattern

will help reduce noise.

(Reference: Place wire antenna to suspicious I/O to amplify noise element to locate noise

origination.)

Confidential 53

TRH03XM COOK BOOK

Chapter8 Air interface Measurement

8.1 Air interface

Air interface, when RF Transceiver is configured, is a gage to know whether Analog part PHY

(physical layer) satisfies electrical specifications. Air interface exact waveform standard are listed

in each protocol documents. However, protocol test standard document do not list exact

waveform test method in air interface but using standard documentation, air interface waveform

test method and actual results are listed. ISO/IEC air interface standard can be confirmed using

TRH03XM to enhance credibility and understanding functionality of Reader IC.

8.2 Measurement

Between reader and tag communication, confirm transmitted data to trigger signal in reader

and antenna voltage from modulation.

Tektronix TDS5104B

(a) Antenna equivalent model (b) Equipment (Oscilloscope)

Picture 8-1 Measurement Point


TRH03XM COOK BOOK

www.3ALogics.com |

8.3 100% ASK Waveform

1) ISO/IEC 14443A

(a) ISO/IEC 14443A (b) RSK Board Modulation Waveform

Picture8-2 100% ASK Modulation Waveform

Chart 8-1 100% ASK Modulation Index

RSK Board Results ISO/IEC 14443 Specification

t1 2.32μs 2 ~ 3μs

t2 0.74μs 0.7 ~ 3μs

t3 0.36μs 0 ~ 1.5μs

t4 0.22μs 1 ~ 0.4μs

Confidential 55

TRH03XM COOK BOOK

2) ISO/IEC 15693

(a) ISO/IEC 15693 (b) RSK Board Modulation Waveform

Picture 8-3 100% ASK Modulation Waveform

Chart 8-2 100% ASK Modulation Index


t1 9.36μs 6 ~ 9.44μs

t2 8.72μs 2.1 ~ 9.44μs

t3 0.48μs 0 ~ 4.5μs

t4 0.34μs 0 ~ 0.8μs


TRH03XM COOK BOOK

www.3ALogics.com |

8.4 10~30% ASK Waveform

1) ISO/IEC 14443B

(a) ISO/IEC 14443B (b) RSK Board Modulation Waveform

Picture 8-4 10% ASK modulation waveform

Chart 8-3 10% ASK modulation Index

RSK board results ISO/IEC 14443 specification

tf 0.34μs 2μs max

tr 0.34μs 2μs max

hf, hr 0.2v 0.4v max

Modulation

Index

10%

(6 ~ 45 %) 8 ~ 14%

Confidential 57

TRH03XM COOK BOOK

2) ISO/IEC 15693

(a) ISO/IEC 15693 (b) RSK Board Modulation Waveform

Picture 8-5 10% ASK Modulation Waveform

Chart 8-4 10% ASK modulation Index


t1 9.4μs 6 ~ 9.44μs max

t2 9.16μs 3 ~ 9.44μs

t3 0.36μs 0 ~ 4.5μs

hf, hr 0.2v 0.4v max

Modulation

index

10%

( 6 ~ 43 % ) 10 ~ 30%


TRH03XM COOK BOOK

www.3ALogics.com |

Chapter9 Modulation Index Control

9.1 Modulator Concept

TRH03XM transmitter driver comprises of main driver transferring tag electric power and

modulation driver that controls modulation index.

Picture 9-1 Transmitter Driver Block Diagram

Chart 9-1 Transmitter Control Register Map

Address Name Initial Description Value

7 6 5 4 3 2 1 0

0x11 Txcontrol 58 • Antenna driver control 0 Modulator

source

ASK

100

TX2

inv

TX2

nomod

TX2

en

TX1

en

0x12 Cwconductance 3F • Antenna driver conductance 0 0 Cwconductance

0x13 Modconductance 04 • Modulation Conductance 0 0 Modconductance

Confidential 59

TRH03XM COOK BOOK

This two drivers are controlled by Txcontrol register[0x11] and each driver output is controlled

by [0x12], [0x13] register that controls conductance. As in Picture 9-2, (a) 100% ASK modulation

occurs by main driver switching, (b) 10% ASK modulates by main driver and modulation drivers

elected signal.

MainModulation

TX_I TX_ANT

(a) 100% ASK Waveform (b) 10% ASK Waveform

Picture 9-2 ASK Modulation Waveform

9.2 Modulator Index Adjustment

1) Standard Modulation Index

- ISO/IEC 14443 A type: 100%

- ISO/IEC 14443 B type: 8% ~ 14%

- ISO/IEC 15693: 100% or 10% ~ 30%

- ISO/IEC 18092 and Felica: 8% ~ 30%

(For other protocols please refer to each protocol modulation index.)


TRH03XM COOK BOOK


2) Modulation Index Control

Modulation index can be adjusted using register [0x13]. Adjustment is for all standard

specifications except basic 100% ASK switching operation.

Chart 9-2 TRH031M Modulation Index (3ALogics TEST board)

Value Index (%) Value Index (%) Value Index (%)

01 25.7 16 4.1 2B 2.9

02 18.6 17 3.2 2C 3.6

03 9.5 18 5.4 2D 2.9

04 14.2 19 4.0 2E 2.8

05 8.5 1A 3.9 2F 2.3

06 7.7 1B 2.9 30 4.8

07 5.4 1C 3.6 31 3.7

08 12.9 1D 2.9 32 3.6

09 7.7 1E 2.8 33 2.9

0A 7.0 1F 2.2 34 3.4

0B 5.1 20 8.9 35 2.8

0C 6.5 21 6.0 36 2.6

0D 4.8 22 5.7 37 2.3

0E 4.5 23 4.1 38 3.2

0F 3.4 24 5.3 39 2.6

10 11 25 4.0 3A 2.6

11 7.0 26 4.0 3B 3.9

12 6.3 27 3.4 3C 2.5

13 4.8 28 5.0 3D 2.2

14 6.0 29 3.9 3E 2.0

15 4.3 2A 3.7 3F 1.7

TRH03XM COOK BOOK


Chart 9-3 TRH033M Modulation Index (3ALogics TEST board)

Value Index (%) Value Index (%) Value Index (%)

01 41.9 16 6.5 2B 4.8

02 30.9 17 5.6 2C 5.1

03 18.7 18 7.8 2D 4.5

04 23.7 19 6.5 2E 4.3

05 15.0 1A 6.1 2F 3.9

06 12.9 1B 5.1 30 6.5

07 9.6 1C 5.6 31 5.6

08 18.9 1D 5.0 32 5.1

09 12.7 1E 4.7 33 4.5

0A 11.0 1F 4.2 34 4.8

0B 8.5 20 12.9 35 4.2

0C 9.7 21 9.6 36 4.0

0D 7.8 22 8.5 37 3.5

0E 7.2 23 7.2 38 4.5

0F 6.1 24 7.8 39 4.0

10 15.2 25 6.5 3A 3.9

11 10.9 26 6.1 3B 3.4

12 9.4 27 5.3 3C 3.7

13 7.8 28 7.0 3D 3.2

14 7.7 29 6.0 3E 3.1

15 7.0 2A 5.6 3F 2.7

Chart 9-2 and 9-3 are measured value maximizing (a) Cwcondutance [0x12: 3F] and adjusting

Modconductance [0x13]. These values are based on 3ALogics boards offered as RSK board. If

applied to different system, these values may differ because antenna, components, and other

conditions are not the same.

TRH03XM COOK BOOK


9.3 Adjustment Guide

Modulation index can be adjusted using 6 bit total of 64 steps but not all values are used.

Based on system and antenna size these values differ but user can use Chart 9-4 and 9-5 as

reference when using similar size antenna. Use as Quick Guide these value meet air interface

standard by protocol and there are total of 10 steps with 01~3F.

Chart 9-4 TRH031M Modulation Index Adjustment Quick Guide

(a) Small size antenna: 45mm X 35mm, for digital door lock

Value 01 02 04 08 10 20 21 30 31 3F

Index

(%) 14.6 11.6 9.8 8.3 7.1 5.7 4.1 3.5 2.9 1.6

(b) Medium size antenna: 75mm X 50mm, Card and ID-1 size

Value 01 02 04 08 10 20 21 30 31 3F

Index

(%) 25.7 18.6 14.2 12.9 11 8.9 6.0 4.8 3.7 1.7

(c) Large size antenna: 75mm X 75mm, ISO/IEC 15693 extended reading distance

Value 01 02 04 08 10 20 21 30 31 3F

Index

(%) 18.3 14.1 11.6 10.0 8.5 6.9 5.0 4.1 3.3 1.7

RSK100 setting [0X13]

- ISO/IEC 14443 B-type: 04

- ISO/IEC 15693: 00 or 10

(Set 100% ASK protocol with 00)

TRH03XM COOK BOOK


Chart 9-5 TRH033M Modulation Index Adjustment Quick Guide

(a) Small size antenna: 45mm X 35mm, for digital door lock

Value 01 02 04 08 10 20 21 30 31 3F

Index

(%) 28.7 19.3 14.2 11.1 9.2 8.1 6.2 4.5 4.0 2.6

(b) Medium size antenna: 75mm X 50mm / Card , ID-1 size

Value 01 02 04 08 10 20 21 30 31 3F

Index

(%) 41.9 30.9 23.7 18.9 15.2 12.9 9.6 6.5 5.6 2.7

(c) Large size antenna: 75mm X 75mm / ISO/IEC 15693 extended reading distance

Value 01 02 04 08 10 20 21 30 31 3F

Index

(%) 34.5 24.2 17.6 13.8 11.0 9.6 7.3 5.3 4.7 2.5

RSK300 setting [0x13]

- ISO/IEC 14443 B-type: 10

- ISO/IEC 15693: 00 or 10

- Felica: 10

(Set 100% ASK protocol with 00)

TRH03XM COOK BOOK

www.3ALogics.com |

Chapter10 Understanding Demodulation

Actions

10.1 What is Demodulation?

Demodulation is simply the conversion of a modulated carrier wave into a current equivalent to

the original signal. Demodulation is the act of removing the modulation from an analog signal

to get the original baseband signal back. Demodulating is necessary because the receiver system

receives a modulated signal with specific characteristics and it needs to turn it to base-band.

There are several ways of demodulation depending on what parameters of the base-band signal

are transmitted in the carrier signal, such as amplitude, frequency or phase.

Picture 10-1 HF RFID Demodulation Overview

Picture 10-1 is simple demodulation overview. It’s half duplex data transfer method that

displays modulation by reader modulation and tag load modulation while energy is supplied

continuously. Data demodulation by this load modulation is major role of reader receiver.

Confidential 65

TRH03XM COOK BOOK


10.2 Demodulation Register

Chart 10-1 is Receiver control register map. VGA (Variable Gain Amplifier) is a block to amplifier

minute analog signal that rectified through rectifier and able to change gain value. From average

RF system RSSI (Received Signal Strength indicator) receives feedback data by strength of receiver

signal and automatically changes AGC (Automatic gain controller) gain, but HF RFID system does

not automatically change gain. It’s because load modulation data signal is not consistent based

on distance and strength of RX carrier wave as well as maximum strength receiver can receive is

pre-determined. Basically received strength and size of carrier wave do not impact data size.

System without noise set gain [0x19] to maximum value of 05 without any harm but typically set

to 03. To maximize performance user can adjust in software level setting gain from 00 to 05.

Chart 10-1 Receiver Control Register Map


7 6 5 4 3 2 1 0

0x19 Rxcontrol1 02

• VGA gain control

( filter default gain : 27.6dB )

101 – 21.58dB, 100 – 20.00dB

011 – 18.06dB, 010 – 15.56dB

001 – 12.04dB, 000 – 06.02dB

0 0 0 0 0 VGA gain

0x1C Rxthreshold 18

• Comparator reference voltage control

101 – 1.560v, 100 – 1.591v

011 – 1.621v, 010 – 1.681v

001 – 1.713v, 000 – 1.743v

• Hysteresis range (peak to peak)

101 – 256mv, 100 – 216mv

011 – 180mv, 010 - 144mv

001 – 106mv, 000 – 068mv

0

Com.

Ref.

On

Hysteresis

range

Comparator

Ref. voltage

Comparator is a block to convert analog signal to digital signal. Reference voltage is not used

unless external components filtering are not adequate or impact of offset is big. Hysteresis range

is used to protect data from changes affected by noise. Threshold is increased and decreased

to reduce noise. Basically register[0x1C] value is set to 18.

(Comparator: 000 / Hysteresis range: 011 / Comparator reference voltage control On: 0)

TRH03XM COOK BOOK


RSK 100 setting [0X19] / [0X1C]

- ISO/IEC 14443 A-type: 03 / 18

- ISO/IEC 14443 B-type: 03 / 18

- ISO/IEC 15693: 03 / 18

- Tag-it: 03 / 18

RSK 300 setting [0X19] / [0X1C]

- ISO/IEC 14443 A-type: 03 / 18

- ISO/IEC 14443 B-type: 03 / 18

- ISO/IEC 15693: 03 / 18

- Tag-it: 03 / 18

- I-CODE: 03 / 18

- Jewel: 03 / 18

- Inside: 03 / 18

- Felica: 01 / 5A and 01 / 18 and 01 / 5B register value sweep

Receiver register setting for all protocols (except Felica) are same. Compared to other

protocols, Felica frequency carrier wave is low and amplitude change by load modulation is very

small. For various Felica tag reading, register value change is necessary. Only for Felica protocol

switch comparator reference value from default value up and down for use. For RSK board as an

example, fix Gain to 12.04dB and Hysteresis range to 180mV but change comparator reference

value.

TRH03XM COOK BOOK

10.3 Demodulation Signal Measurement

1) Measurement Set up

Demodulation signal can be surveyed using TRH03XM #1 pin TESTOUT. As seen on Picture

10-2, change register [0x26] to select signal for probing.


Test output control

TESTOUT

LOW

HIGH

Card response envelope signal

Decoded signal

Coded signal

Oscilloscope probing

< Register Address : 26H >

<00>

<01>

<02>

<03>

<04>

Card detector output

<05>

Picture 10-2 TEST Output Control Block Diagram

(Register 05 value only applies to TRH033M chip.)

TRH03XM COOK BOOK

www.3ALogics.com |

2) Measurement

TESTOUT (26H: 02 , ENVELOPE SIGNAL) TX1 ANTENNA

- ISO/IEC 14443 A-type (Manchester / OOK 847kHz subc.)

(a) A-type Card Response

(b) Envelope Signal

Confidential 69

Picture 10-3 14443A Demodulation Waveform

TRH03XM COOK BOOK

- ISO/IEC 14443 B-TYPE (NRZ / BPSK SUBC.)

(a) B-type Card Response

(b) Envelope Signal (Phase Shift Section)

Picture 10-4 14443B Demodulation Waveform

- ISO/IEC 15693 (Manchester / OOK subc.)


TRH03XM COOK BOOK

www.3ALogics.com |

(a) 15693 Card Response

(b) Envelope Signal

Picture 10-5 15693 Demodulation Waveform

Confidential 71

TRH03XM COOK BOOK

Chapter11 Using Card detector

11.1 Card Detector Principle

As seen in Picture 11-1, Card detector generates carrier wave only without modulation for data

transmission from reader. When tag is not available, original power output is transmitted

through antenna, but when tag is available, antenna current flows reversely to mutual inductance

by tag coil, thus, carrier wave (basically voltage) is lowered. Detecting voltage change is the role

of card detector.

Picture 11-1 Carrier Signal Reduction by Tag

11.2 Card Detector Application


Card detector is effective to reduce electric power use when card does not exist. Products such

as digital door lock, locker with RF keys, PDA and handheld RFID reader that do not have

constant electric source are ideal for card detector functions.

TRH03XM COOK BOOK


11.3 Card Detector Movement

1) Card Detector Basic Movement

Card detector is only available in TRH033M chip and it comprises of rectifier block, DAC,

Comparator Amp. From 3ALogics own proprietary patent, circuit converts carrier wave AC signal

to DC and compare this DC value to threshold voltage to output comparable signal. Low value,

from DC output converted by threshold voltage, to logic 0 and high value to logic 1 output to

detect card.

2) Card Detector Register Map

Card detector block control registers are listed in Chart 11-1. System applying card detector

and reference level register [0x32] impacting detection performance are 6 bit and voltage control

can be done between 1.05V to 2.25V.

Chart 11-1 Card Detector Register Map


7 6 5 4 3 2 1 0

0x32 DETECTLEVEL 00

• DAC reference level

ref vol. : 1.05 ~ 2.25 ( 1LSB 75mV )

000000 – 00 : 1.05 + 1LSB

111111 – 3F : 2.25

0 0 Detectlevel

0x33 DETECTREG 00 • Detect register

DetectOn : high enable DetectOn 0 0 DetectTime DetectFlag 0

Register[0x33] controls card detector including DetectOn (Enabling flag), DetectFlag bit (Displays

existence of card), and DetectTime flag (Store time management). Bit 0 is not used and

DetectTime can be use with Default with 00. Time delay according to DetectTime flag is listed

below.

- 000 : 5us Detection Set Time 001 : 10us Detection Set Time

- 010 : 15us Detection Set Time 011 : 20us Detection Set Time

- 1xx : 40us Detection Set Time

TRH03XM COOK BOOK


11.4 Card Detector Set-up Procedure

Below is card detector set up process. To minimize power consumption while detecting only

turn on minimum driver while transmitting carrier wave.

1) 0X11: 01, 0X12: 00, 0X13: 01, 0X26: 05, 0X32: 00, 0X33: 80 Register initial value setting for

card detection

2) Receiver RX signal pk-pk confirm (#26 pin)

Example: RX 980mV

3) Change 0X13 Register for RX pk-pk signal to have more than 1.0V input: 02 04 08 10

20

Example: Change 0X13 -> 02, RX 1.12V OK

- If Register value is high than error will decrease but current consumption will slightly

increase. 02 setting is only an example. 20 is recommended.

*** But, to reduce error in sample case, if increasing current does not impact system

current consumption, 0x12 Register instead of 0x13 Register for card detection operation

is ok.

4) More than 10 test samples for RX signal pk-pk Check (Cf. EMC LC filter: High device

tolerance components used.)

Example:

1번 2번 3번 4번 5번 6번 7번 8번 9번 10번 11번 12번 13번 14번 15번

1.12 1.11 1.14 1.12 1.14 1.12 1.12 1.12 1.14 1.105 1.10 1.11 1.12 1.11 1.12

5) Select best pk-pk signal sample (For all sample case to be detected, select lowest sample

case of AC to DC conversion level)

Example: #10

6) Raise selected sample Register 0X32 (00 ~ 3F) and search for low Register value

Example: #10 00 ~ 06 -> high, 07 -> low

7) Conclude Register value from Low Register to Standard (Lower 1 to 2 steps)

Example: 05 or 06

8) Register value search complete.

Example: Register value used in Card detection

0X11: 01 - Tx control (TX2 off and TX modulator source low, 100% ASK disable)

0X12: 00 - Cw-Conductance off

TRH03XM COOK BOOK

www.3ALogics.com |

0X13: 02 - Mod-Conductance

0X32: 05 or 06 - Card detector reference voltage

0X33: 80 - Card detector enable

Card detector detects by slight voltage reduction rather than data receiving, thus, error

occurrence is high compared to sample demodulation process. Therefore, multiple sample tests

are required before register setting for improved result.

11.5 Practical Application

Using 45mm X 35mm Antenna as a standard, current system configuration detects card twice in

1 second. Enabling 1.25msec card detector for 500msec, system current consumption is 19.3mA

so total current consumption calculation is 48.25uA.

- Current Calculation

TVDD 11.5mA + AVDD: 3.2mA + DVDD: 4.6mA = 19.3mA

1.25msec X 19.3mA / 500msec = 48.25uA

Actual calculated value using Multi-meter is approximately 38uA and different from calculated

value. Calculated value is assuming 1.25msec carrier wave transmitting, and actual value detected

about 20% less current.

Picture 11-2 displays waveform measured using Oscilloscope to see card detector operation.

Depending on system and board, RST time and Carrier on time adjustment (lower) is possible and

power consumption can be reduced further.

TESTOUT : 1번 pin

RST : 22번 pin

RX : 26번 pin

1.25ms

Carrier on time : 260u

Card : X Card : O

(a) Card Not Available (b) Card Available

Confidential 75

Picture 11-2 Card Detector Operation Mode Waveform

TRH03XM COOK BOOK


- Battery life calculation

** Ni-Cd (Nickel Cadmium): 1.5V, 700mAh ~ 800mAh

Ni-MH(Nickel-hydride): 1.5V, 2100mAh ~ 2500mAh

(What is mAh?: Current mA used in 1hr. Example: 2500mAh / 250mA = 10hr. Basically

1.5V MP3 with 250mA current consumption can use 10hrs of battery. Compared to Ni-MH,

battery use is extended for 1.5x~2x of normal battery consumption.)

** Ni-MH 1.5V 2500mAh Standard (DDL set: AA size 4 Alkaline Batteries)

Electric power 1.5V 4ea series, P = 6V X 2500mAh = 15000mWh

(Fix current since it is series)

P = 3.3V X 38uA = 125.4uW

15000mWh/125.4uW = 119617.2 hours = 4984 days = 13.65 years

RSK 300 setting

Mod-driver cwconductance / Detection carrier power [0x13]: 04

Detector reference level [0x32]: 05

TRH03XM COOK BOOK

www.3ALogics.com |

[Reference]

[1] International Standard ‘ISO/IEC 14443‘, Part II

[2] International Standard ‘ISO/IEC 15693’, Part II

[3] Young Yoon, ‘RF Active Circuit Design Theory and Practical Use’, Hongreung Science

Publishing, Chapter6, 2005

[4] Dae Jin Cho, ‘RFID Theory and Applications ‘, Hongreung Science Publishing, Chapter 1,

2005

[5] Klaus Finkenzeller ‘ RFID HABDBOOK ‘, Youngjin.com, Chapter 4, 2004

3ALogics 13.56MHz Multi-protocol RFID reader IC Cook Book

It’s RFID

RFID & Mobile SoC for Ubiquitous Technology

Contact

3ALogics Inc. 7th Fl., Hyundai-office Bldg., 9-4, Sunae-dong,

Bundang-gu, Seongnam-si, Gyeonggi-do, 463-783

Korea

TEL: (82)-(31)-715-7117

FAX: (82)-(31)-719-7551

Homepage: http://www.3ALogics.com

Email : [email protected]

Printed in the Republic of Korea.

Confidential 77

후리그냥 낭탕 워 - maritexdownload.maritex.com.pl/pdfs/wi/trh03xm-cook.pdf · rfid system...

Documents