Andreas Ishak Loza1

Giuseppe Li Puma1, Ernst Kristan1, Paolo De Nicola2, Cyril Vannier3,

Braam Greyling4, Salvatore Piccolella5

K

Duisburg, Germany1, Sophia-Antipolis, France2, Xi’an, China3 ,Villach, Austria4, Padova, Italy5

SiP for GSM/EDGE in CMOS Technology

Infineon Technologies AGU.R.S.I. – Kleinheubacher Tagung 2008

Outline

• Motivation

• System Overview

• RF-Integration Aspects

• Measurement Results

Motivation• Integration of RF+BB and PMU in CMOS • Benefits of SiP

– BOM reduction– Small Form Factor

• Customer ease– Fewer board spins– Less validation effort– Faster development

Advantages of SiP• Exploitation of mature existing solutions

• Reduces chip development time

• Lowers risk of crosstalks

• Offers possibility of stacked chipscaletechnology– Logic-Memory Stacking

System Overview

Micrograph• BB+RF SoC

– 0.13 µm CMOS– 6 Metal layers– MIM-capacitors– 20Ωcm substrate– bumps over

active area– w/o deep trench,

triple well

• PMU– 0.25 µm CMOS– thick top metal

layer– 5V capability

RXLNA+MixFilterADC

PLL+

VCO

TX

DCXO Digital

Block Diagram of RF-Part• RX

- Quad-band Zero-IF- 3rd order Channel-filter- 87dB 3rd CT-Σ∆ ADC- Noise Figure 2.4dB- AM Suppression 88dB

• TX- linear polar modulator- closed loop power control+6dBm output power

• Two 26MHz outputbuffers

• Digital Interface to BB

RF-Integration Challenges• Crosstalk

– PMU to RF coupling– BB to RF coupling

Technology Trend

- Number digital gates

- Clock frequency

- I/O-interface speeddigital noise increases

• Thermal effectsFrequency

Synthesizer

TX2

4

DCXO

Package• Increased

routing complexity– 2 distribution layers

• Packagecrosstalk effects– inter-package– package-to-chip RF MS

BB

PMU

TxM

ext.Device

RX-SAW

Crosstalk Analysis• Example:

Coupling into VCO Supply– spurious tone:

– AM/FM conversion– sensitivity factor:

– single sideband to carrier ratio:

– PLL transfer characteristic inherentlysuppresses spurs within loop bandwidth

• similar analysis applicable to LO-path and Driver– AM/AM and AM/PM conversion

VDDVCOFM VfK ∆∆=

)2()( 111 fAKfSSCR FM=

)2cos( 11 tfA π

1

1

2 fAKA FM

c

cA

Schematic of the VCO• Separate supply

voltage and ground

• Supply blocking

• Substrate shielding

• Reduce thermal stress

VbatVbg

Ctune

VDDLO

VDDVCO

Step Down Converter• High PSRR of RF-LDO needed to meet GSM

specification mask

0 5 10 15 20-150

-130

-110

-90

-70

-50

f [MHz]

Rip

ple

[dB

Vp]

Measured Phase Noise Spectrum

• Measured withrunning BB andPMU

• Sideband tone @ 925kHz due to DC/DC switchingfrequency

Temperature Distribution• Package • On-Chip

RFMS

BBPMUBB

RFMSPMU

• PMU is major heat source contributor• Reduced thermal stress of RF-part due to separation

-90

-85

-80

-75

-70

-65

-60

-55

-50

910 920 930 940 950 960 970 980 990Frequency [MHz]

TX p

ower

in R

X ba

nds

[dB

m] RX band E-GSM 900

RX band GSM 900

limit due to GSM specification

Measured TX Spectrum in GSM900 RX Bands at 914.8MHz Carrier Frequency

fTX+52MHz moves with carrier

26MHz harmonics

EDGE Modulation Mask @ ±400kHz

• PRBS EDGE modulation with running PMU and BB

• Measured output power @ ± 400kHz offset from carrier for GSM high- and low bands

• Sufficient margin to GSM specification limits

Spec. Limit Spec. Limit

-75

-70

-65

-60

-55

-50

1700 1730 1760 1790 1820 1850 1880 1910freq. [MHz]

spec

trum

[dB

c]-400kHz

+400kHz

Spec. Limit

GSM 1800 GSM 1900

Spec Limit Spec Limit

-75

-70

-65

-60

-55

-50

820 840 860 880 900 920freq. [MHz]

spec

trum

[dB

c]

-400kHz+400kHzSpec Limit

GSM 850 EGSM 900

EVM for High- and Low Bands• PRBS EDGE

modulation with running PMU and BB

• EVM for high- and low bands

• sufficient margin to GSM specification limits

820 840 860 880 900 9200

2

4

6

8

10

EV

M [

%]

1700 1750 1800 1850 19000

2

4

6

8

10

Frequency [MHz]

EV

M [

%]

EVM AvgEVM Hold

GSM800 GSM900

GSM1800 GSM1900

Limit Limit

LimitLimit

Receiver Sensitivity• Measured

sensitivity withrunning BB and PMU

• No degradationobservable duetointegration

• Achievedperformance iscomparable to stand-alonetransceivers

860 880 900 920 940 960-113

-112

-111

Ref

.Sen

s. [

dBm

]

Class 2 BER 2.4%

Frequency [MHz]

GSM 850GSM 900

1800 1850 1900 1950 2000-113

-112

-111

Frequency [MHz]

Ref

.Sen

s. [

dBm

]

GSM 1800GSM 1900

Conclusion• SiP with integrated highly efficient power

management-unit

• Fabricated in standard CMOS technologies

• RF-performance is comparable to stand-alone CMOS transceivers

• Careful floorplanning, package routing, supply and ground partitioning is mandatory