1. A Zero-IF 60GHz Transceiver in 65nm CMOS with > 3.5Gb/s Links
Alexander Tomkins, Ricardo A. Aroca, Takuji Yamamoto*, Sean T. Nicolson, Yoshiyasu Doi* and Sorin P. Voinigescu, University of Toronto, Toronto, Canada, *Fujitsu Laboratories, Kawasaki, Japan
University of Toronto 2008

2. Alexander Tomkins – University of Toronto 2008
System Description
Simple architecture appropriate for rapid file-transfer -> “Kiosk” applications
Fundamental frequency, zero-IF architecture
Direct BPSK modulation/demodulation
Baseband NRZ data recovered with no ADC
Single-chip with TX and RX integration
Design completed in 3-4 weeks (4 designers), with an immature design-kit
Performed hand design with only DC sims and no layout parasitic extraction tool.
Designed for 60GHz + 10%
Alexander Tomkins – University of Toronto 2008

3. Circuit Design Philosophy in CMOS
*A 65nm CMOS wafer costs more than a 300GHz SiGe BiCMOS wafer*
CMOS does not make economic sense unless you integrate the DSP
You must ensure that all topologies can scale to 45nm, 32nm ...
Tradition cascode stages:
Require VDD≥1.0
VDS will vary as a result of VT variation
Different topologies are required in order to:
Work with VDD < 0.9V
VT insensitive
VDD ≥ 1.0V
∆ VT
∆VDS due to ∆ VT
Alexander Tomkins – University of Toronto 2008

4. Circuit Design Philosophy in CMOS
Folded-cascode topologies with constant current biasing
Only one high-speed transistor is placed between VDD and ground, maximizing the transistor VDS.
All mm-wave blocks can be implemented with these topologies:
AC-folded Cascode
XFMR-folded Cascode
But there is a price: 2x the current
Alexander Tomkins – University of Toronto 2008

5. Low-Noise (Power) Amplifier
Input is noise and impedance matched to 50Ω, with large output transistors for IIP3 and OP1dB
80mA (60mA) from 1.2V (1.0V)
High gain to reduce receiver NF variation with temperature/process
Alexander Tomkins – University of Toronto 2008

6. Direct BPSK Modulator and Mixer
Data signal directly drives quad transistors of modulator [in SiGe: C. Lee et al, CSICS 2004]
Equivalent to a digitally modulated PA; operates in saturation
Both circuits drive off-chip directly in 50Ω (mixer has no IF amplifier)
Alexander Tomkins – University of Toronto 2008

7. New Frequency Divider Topology
Merged latching quads minimize feed-back path
220um
85um
Single differential pair drives both latches:
Reduces footprint, increases speed
saves power and area
Alexander Tomkins – University of Toronto 2008

8. Transceiver Implementation – Die Photo
Alexander Tomkins – University of Toronto 2008

9. Transceiver Implementation - Technology
Fujitsu 65nm CMOS
7-metal back-end, MiM capacitors
Alexander Tomkins – University of Toronto 2008

10. Low-Noise (Power) Amplifier
Measurements
Peak gain of ~19dB, S11 better than -10dB up to 65GHz
25oC, 1.2V: IP1dB = -14dBm, OP1dB = +2.5dBm, PSAT = +7.5dBm
Alexander Tomkins – University of Toronto 2008

11. Frequency Divider Measurement (from TXRX)
Alexander Tomkins – University of Toronto 2008

12. Measured Receiver Gain and NF over Process Corners
Alexander Tomkins – University of Toronto 2008

13. Measured Receiver Gain and NF Over Temperature and Power Supply
Alexander Tomkins – University of Toronto 2008

14. Alexander Tomkins – University of Toronto 2008
Measured Transmitter Output Power vs. Frequency over Temperature and VDD
61GHz Carrier, 4.0Gbps PRBS Signal
Alexander Tomkins – University of Toronto 2008

15. Transmit-Receive Link Experiment
Alexander Tomkins – University of Toronto 2008

16. Transmit-Receive Test Setup
External 4GHz IF Amplifier
Received Eye
RX Antenna (25dBi)
Receiver Probe-station
Received Spectrum
PRBS Generator
TX Antenna (25dBi)
Transmitter Probe-station (not in shot)
~2m
Alexander Tomkins – University of Toronto 2008

17. Transmit-Receive Test Results – 4Gb/s @ 50°CRX
60.8GHz Carrier
4.0Gbps 27-1 PRBS Signal
50°C, room temperature TX
Alexander Tomkins – University of Toronto 2008

18. Transmit-Receive Test Results – 6Gb/sRX
60.8GHz Carrier
6.0Gbps 27-1 PRBS Signal
Testing limited by bandwidth of IF amplifier (4GHz) TX
Alexander Tomkins – University of Toronto 2008

19. Alexander Tomkins – University of Toronto 2008
Summary
1.2V 60GHz zero-IF single-chip transceiver in 65nm CMOS
Occupies only 1.28x0.81mm2 (1.0mm2), consumes 374mW
Simple high-bandwidth, high data-rate architecture
Proof-of-concept demonstration: wireless link over 2m
Data-rates up to 6.0Gb/s demonstrated (IF bandwidth limited above 4GHz)
First demonstration of a 60GHz wireless link at 50oC
60GHz transceiver block characterization over process corners, temperature, and power supply.
Alexander Tomkins – University of Toronto 2008

20. Alexander Tomkins – University of Toronto 2008
Acknowledgements
This work was funded by Fujitsu Limited.
Many thanks to Katya Laskin and Ioannis Sarkas for testing, measurement, and lab support.
The authors would like to thank Jaro Pristupa and CMC for CAD support, CFI, OIT, and ECTI for test equipment.
We would also like to thank Dr. W. Walker of Fujitsu Laboratories of America Inc. for his support.
Alexander Tomkins – University of Toronto 2008

21. Alexander Tomkins – University of Toronto 2008
Backup
Alexander Tomkins – University of Toronto 2008

22. 60GHz SPST Switch (Stand-alone)
Tuned SPST switch for 60GHz operation
High-isolation from series-shunt transistor and 250pH inductor
Lower-insertion loss from 45pH shunt inductor
Alexander Tomkins – University of Toronto 2008

23. Transmit-Receive Link Experiment
Goal: Demonstrate successful data transmission
“Bits in, bits out”
Single-ended input data stream (PRBS sequence) fed directly on-chip
Data stream reclaimed directly from the receiver IF output with no ADC
One probe-station will act as a transmitter, one as receiver
Transmit channel formed by:
2m wireless link with transmitter/receiver 25dBi horn antenna
Total channel loss (including input/output losses): 35dB
Lack of on-chip IF-amp requires an additional external amplifier (limited to 4GHz BW)
Alexander Tomkins – University of Toronto 2008

24. Transmit-Receive Test Results
60.8GHz Carrier
2.0Gbps 27-1 PRBS Signal
50°C, room temperature
Alexander Tomkins – University of Toronto 2008

25. Alexander Tomkins – University of Toronto 2008
Comparison Table
Alexander Tomkins – University of Toronto 2008