Coupled Dual LC Tanks based ILFD with Low Injection Power and

Compact Size

presented by

Mahalingam Nagarajan

Research Associate

School of EEE, Nanyang Technological University, Singapore

02-10-2014

Outline

Motivation

Background and Fundamentals

Operating principle, performance metrics of ILFD

Different ILFD topologies

Proposed ILFD

Design challenges in ILFD design

Proposed ILFD

Results and Discussion

Conclusion and Future work

2

Motivation

Unlicensed band around 60 GHz

Large channel bandwidth

Giga-bits-per-second

applications

3 Smulders P: Exploiting the 60 GHz Band for Local Wireless Multimedia Access: Prospects and Future Directions, IEEE Communications

Magazine, pp. 140-147, January 2002.

Motivation - High Frequency Divider

Important Specifications

Locking Range

Power consumption

Phase noise

Output power and efficiency

Design Challenges

High frequency of operation

Wide locking range with low injected power levels

High output power to drive subsequent blocks with low power

consumption

4

Static Frequency Divider

Popular topology based on Ring

oscillator.

Oscillation condition:

Advantages

Wide locking range

Small layout area

Drawbacks

High power consumption

Poor phase noise

5

LLCRf

2

1max

1 LML Rg

U. Singh, and M. Green, “High Frequency CML Clock Divider in 0.13µm CMOS Operating up to 38 GHz,” IEEE J. Solid-State Circuits, vol.

40, no. 8, pp 1658-1661, Aug. 2005.

Injection Locked Frequency Divider

Popular topologies

Ring Oscillator based ILFD

LC based ILFD

Advantages

High frequency of operation

Low power consumption

High output power & Low phase

noise

Drawbacks

Narrow locking range

Large layout area

6 C.-C. Chen, H.-W. Tsao, and H. Wang, “Design and analysis of CMOS frequency dividers with wide input locking ranges”, IEEE Trans.

Microw. Theory Tech., vol. 57, no. 12, pp 3060-3069, Dec. 2009.

Injection Locked Frequency Divider Design Challenge

Locking Range of ILFD

Important Parameters

Injection power or efficiency (Iinj)

Quality factor of tank circuit

ILFD core current (Iosc)

How to increase the locking range at low injected power level?

either quality factor of the tank circuit or ILFD core current has to decrease.

Drawbacks?

Yes, high power consumption, low output power, poor phase noise

7

osc

inj

o IQ

I

2

Injection Locked Frequency Divider based on Coupled Dual LC tanks

Cross-coupled oscillator

topology

Coupled dual LC tank

Differential injection

transistor topology

PMOS current source to

reduce noise

Features

Simple topology

Fully differential operation

No additional layout area

8

Analysis of Coupled Dual LC tanks

9

vv

s

v

sCL

CMLLand

CL

RMRR

22

22

1212

222

11

p

injp

L

RRQ

//

)(,,, tVgvgI injinjminjgsinjminj

2,,

injdc

oscmooscmosc

RIgvgI

2,

, .

injdcoscm

piinjm

o RIg

LVg

N. Mahalingam, K. Ma, K. S. Yeo, and W. M. Lim, “Coupled Dual LC Tanks Based ILFD with Low Injection Power and Compact Size,”

IEEE Micro.Wireless and Comp. Let., vol. 24, no. 2, pp. 105–107, Feb. 2014.

ILFD Die microphotograph

10

Tower Jazz 0.18 µm SiGe BiCMOS

process

Fcenter = 12 GHz

PDC = 4.8 mW with 1.8V

Core : 0.22 ×0.29 mm2

Dual coupled coils:

Top Metal thickness: 2.81 µm

Area: 123 ×123 µm2

ILFD Results Locking Range

11

Locking Range: 21.41 GHz – 25.18 GHz (16%) @ -16 dBm input

Output Power: -2.5 dBm to -3.2 dBm

ILFD Results Phase Noise

12

Free-run: -98 dBc/Hz @ 1 MHz offset from 12.5 GHz

Locked Phase noise: 6 dB difference with 25 GHz input

ILFD Results Performance Comparison

13 , # - Core area

Ref This Work [1] [2] [3] [4] [5]

FCENTER (GHz) 24 23 23 28 20 20

LR (%) @

Pin= -10 dBm

Pin = -5 dBm

Pin = 0 dBm

17.16

18.49

25.07

-

10.62

11.76

15.7

17.8

23.7

10.88

13.55

21.47

-

7.06

13.08

-

12

16

PDC (mW) 4.8 4.32 1.5 1.8 1.51 6.4

PN (dBc/Hz)

@ 10 kHz

@1 MHz

-116

-127

-110

-

-110

-131

-105

-124

-108

-123

-108

-126

POUT / PDC (%) 18.56 - 5.29 2.21 10.5 11.06

FOM (%/mW2)

Pin = -10 dBm

Pin = -5 dBm

Pin = 0 dBm

6.63

1.79

0.97

-

-

-

5.55

1.75

0.83

1.33

0.52

0.26

-

1.55

0.90

-

0.65

0.27

Area (mm2) 0.22 × 0.27# 0.7 × 0.7 0.5 × 0.43# 0.83 × 0.54 0.36 × 0.64# 0.33 × 0.08#

Process

Technology

CMOS in 0.18

µm SiGe

BiCMOS

90 nm

CMOS

0.18 µm CMOS 0.18 µm CMOS 0.18 µm CMOS 90 nm

CMOS

DCP

outP

PP

inRangeLockingFOM

DCin

%

Conclusion

The high frequency ILFD divider and the design challenges is

discussed.

High frequency ILFD based on coupled dual LC tanks together with

two differential injection transistor pairs to increase the locking

range while maintaining a high quality factor is presented.

The proposed technique is analyzed theoretically and verified

experimentally with an ILFD operating at 24 GHz achieving a wide

locking range at low injected power levels and higher power

efficiency.

With a compact silicon area and fully differential design, the ILFD

can be readily integrated with low power VCOs.

14

References 1. C.-F. Lee, and S.-L. Jang, “A 24-GHz 90-nm CMOS injection-locked frequency divider,” IEEE Microw. and Optical

Tech. Lett., vol. 51, no. 1, pp. 32-36, Jan. 2009.

2. Y.-H. Kou, J.-H. Tsai, and T.-W. Huang, “A 1.5-mW, 23.6% Frequency Locking Range, 24-GHz Injection-Locked

Frequency Divider,” in IEEE Eur. Microw. Conf., Sep. 2010, pp 73-76.

3. F.-H. Huang, M. -H. Tsai, H.-Y. Chang, and Y.-M. Hsin, “A low power CMOS injection-locked frequency divider based

on Hybrid differential injection technique,” in Proc. Asia-Pacific Microw. Conf., Dec. 2009, pp 301-304.

4. Z.-D. Huang, C.-Y. Wu, and B.-C. Huang, “Design of 24-GHz 0.8-V 1.51-mW Coupling Current-Mode Injection-Locked

Frequency Divider With Wide Locking Range”, IEEE Trans. Microw. Theory Tech., vol. 57, no. 8, pp 1948-1958, Aug.

2009.

5. T. Shibasaki, H. Tamura, K. Kanda, H. Yamaguchi, H. Ogawa and T. Kuroda,”20-GHz Quadrature Injection-Locked LC

Dividers With Enhanced Locking Range,’’ IEEE J. Solid-State Circuits, vol. 43, no. 3, pp 610-618, Mar. 2008.

15

Thank You

16

Q & A

1- Multi-Coupled LC Tanks

17

Primary LC Tank Secondary LC Tanks

2 - Analysis of Multi-Coupled LC Tanks

18

Dual-Coupled LC tanks

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122

,

sss

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2122

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ss

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CL

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DCLC 2

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DCLC

s

so

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LQ

,

,

N. Mahalingam, K. Ma, K. S. Yeo, and W. M. Lim, “A Low Power Push-Push VCO using Multi-Coupled LC Tanks,” Journal of Circuit,

Systems and Computers, vol. 22, no. 10, November 2013.