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Timothy O. Dickson and Sorin P. Voinigescu Edward S. Rogers, Sr. Dept of Electrical and Computer Engineering University of Toronto CSICS November 15, 2006. Low-Power Circuits for a 2.5-V, 10.7-to-86-Gb/s Serial Transmitter in 130-nm SiGe BiCMOS. Outline. Motivation
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Timothy O. Dickson and Sorin P. Voinigescu Edward S. Rogers, Sr. Dept of Electrical and Computer Engineering University of Toronto CSICS November 15, 2006 Low-Power Circuits for a 2.5-V, 10.7-to-86-Gb/s Serial Transmitter in 130-nm SiGe BiCMOS
Outline • Motivation • High-speed, low-power design techniques • 2.5-V, 80-Gb/s BiCMOS Transmitter • Measurement results • Conclusions
1 x 100-Gb/s Next Generation High-Speed Wireline: 100-Gb/s Ethernet New design challenges as fundamental frequencies enter mm-wave regime
Power Consumption should consume less power than 100 Gb/s 10 x 10 Gb/s State-of-the-art High-Speed Transceivers
Power Consumption should consume less power than 100-Gb/s 4:1 MUX?
MOSFETs vs HBTs • HBT @ peak-fT VBE = 900mV… and does not scale! • 130-nm nMOS @ peak-fT VGS = 750mV… and decreasing!
BiCMOS logic family reduces supply voltage Reduce tail current with inductive peaking CLDV2 LP = 3.1 IT2 10 mm Stacked inductors Power reduction techniques 43-GHz latch consumes only 20mW
40-GHz PLL Output Driver On-chip PRBS for BIST 8:1 MUX Transmitter Block Diagram
SF for voltage headroom EF for higher bandwidth 2.5-V, 87-Gb/s BiCMOS Selector 86-Gb/s selector consumes 60mW
2.5-V, 80-Gb/s BiCMOS Pre-Emphasis Driver MOS gm and input capacitance relatively constant as bias current changes. Excellent for output stages with adjustable amplitude control.
2.5-V, 80-Gb/s BiCMOS Pre-Emphasis Driver 130-nm MOSFETs switching at 80-Gb/s!
2.5-V, 80-Gb/s BiCMOS Pre-Emphasis Driver Adjustable pre-emphasis for operation up to 80-Gb/s Boosts high-frequency content to compensate for line losses. Output match S22 < -10dB up to 94 GHz.
36-43 GHz Colpitts VCO • SiGe HBTs used as negative resistance generators. • Differential tuning to reject common-mode noise. • Maximize tank swing, bias HBTs at NFMIN for low phase noise -105 dBc/Hz @ 1-MHz offset
Die Photograph PLL 1.5 mm PRBS + 8:4 MUX 4:1 MUX + Output Driver 1.8 mm
Measured Results: 80-Gb/s Running for more than 1 hour continuously in the lab. Jitter: 560 fs (rms) , Rise/fall time: 4-5 ps, Amplitude: 300 mV
Verification of Correct Multiplexing Using pattern capture capabilities of the Agilent 86100C DCA
Verification of Correct Multiplexing Examine the tone spacing using Agilent E4448A PSA
80-Gb/s: Amplitude Control Little degradation in eye quality as amplitude varies from 100mV to 300 mV per side
Maximum Data Rate: 87-Gb/s 685 MHz 87 GHz = 685 MHz 127
Maximum Data Rate vs. Temp. 92-Gb/s @ 0oC 71-Gb/s @ 100oC
Conclusions • Described methods for power reduction in high-speed building blocks. • Use BiCMOS topology to lower supply voltage. • Trade off bias current for inductive peaking. • Applied these principles to the design of the first 87-Gb/s serial transmitter, which consumes less power than any 40-Gb/s TX reported to date. • As compared with state-of-the-art CMOS, this work shows that you can achieve double the data rate with half the power dissipation simply by adding the SiGe HBT option.
Acknowledgements • STMicroelectronics Crolles for chip fabrication • STMicroelectronics, Gennum, CITO, and NSERC for financial support • CMC for CAD tools • CFI and OIT for equipment and test support
VGS VBE VBE VDS = 0V! VGS DC Considerations Need CM resistor in 43-GHz clock buffer
Future Directions: Futher Power Savings Reduce supply voltage to 1.8V by removing current sources. 38% power savings would result in 86-Gb/s TX that consumes 825 mW.
SiGe Building Block Supply Voltage DC drops dictate at least 3.3-V supply voltage 150 mV IR 900 mV VBE 900 mV VBE 750 mV VCE 600 mV VCE + IR Unlike CMOS, supply voltage does not scale!!
CMOS vs. SiGe BiCMOS SiGe HBT has 2-generation speed advantage