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

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

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

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

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

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

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

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

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

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

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

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

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

Alexander Tomkins – University of Toronto 2008 Measured Transmitter Output Power vs. Frequency over Temperature and VDD 61GHz Carrier, 4.0Gbps 27-1 PRBS Signal Alexander Tomkins – University of Toronto 2008

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

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

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

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

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

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

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

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

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

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

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