A Zero-IF 60GHz Transceiver in 65nm CMOS with > 3.5Gb/s Links

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

2. 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 SiGeBiCMOS 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. Measured Transmitter Output Power vs. Frequency over Temperature and VDD • 61GHz Carrier, 4.0Gbps 27-1 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°C RX • 60.8GHz Carrier • 4.0Gbps 27-1 PRBS Signal • Transmitter @ 50°C, receiver @ room temperature TX Alexander Tomkins – University of Toronto 2008

18. Transmit-Receive Test Results – 6Gb/s RX • 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. 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. Acknowledgements • This work was funded by Fujitsu Limited. • Many thanks to KatyaLaskin and IoannisSarkas for testing, measurement, and lab support. • The authors would like to thank JaroPristupa 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. 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 • Transmitter @ 50°C, receiver @ room temperature Alexander Tomkins – University of Toronto 2008

25. Comparison Table Alexander Tomkins – University of Toronto 2008