1. © Sean Nicolson, BCTM 2006 © Sean Nicolson, 2007 A 2.5V, 77-GHz, Automotive Radar Chipset Sean T. Nicolson 1, Keith A. Tang 1, Kenneth H.K. Yau 1, Pascal Chevalier 2, Bernard Sautreuil 2, and Sorin P. Voinigescu 1 1) Edward S. Rogers, Sr. Dept. of Electrical & Comp. Eng., University of Toronto, Toronto, ON M5S 3G4, Canada 2) STMicroelectronics, 850 rue Jean Monnet, F-38926 Crolles, France WE2B-5

2. © Sean Nicolson, BCTM 2006 © Sean Nicolson, 2007 Outline Motivation Transceiver architecture Circuit design & layout + some device insight Fabrication technology Measurements Conclusions

3. © Sean Nicolson, BCTM 2006 © Sean Nicolson, 2007 Applications W-band applications: 77GHz auto radar, 94GHz weather radar, imaging, data communications All applications require a W-band radio transceiver.

4. © Sean Nicolson, BCTM 2006 © Sean Nicolson, 2007 The Doppler Radar Transceiver Doppler transceiver block diagram Development steps – Design & test circuit blocks + optimize HBT for circuit performance –Integrate circuit blocks into transceiver –Duplicate to form arrays Antennae PA LNA Mixer VCO IF amp To PLL freq. div. Modulation

5. © Sean Nicolson, BCTM 2006 © Sean Nicolson, 2007 Low-noise Amplifier 3-stage design, add R 1 to de-Q the final stage. Noise & impedance matching including C PAD [Nicolson, 2006]. 250  m 1pF decoupling caps

6. © Sean Nicolson, BCTM 2006 © Sean Nicolson, 2007 Power Amplifier Primary goal: maximize PAE –common source, class AB operation

7. © Sean Nicolson, BCTM 2006 © Sean Nicolson, 2007 Down-conversion Mixer Classical Gilbert cell mixer has poor linearity at 2.5V –Eliminate RF pair –Couple to LNA using transformer –Bias quad from center tap Simulations –9dB conversion gain –+3dBm OP1dB (1.25V PP /side) –12.5mW PDC input

8. © Sean Nicolson, BCTM 2006 © Sean Nicolson, 2007 Mixer + IF Amp Layout Layout is critical at 77GHz.

9. © Sean Nicolson, BCTM 2006 © Sean Nicolson, 2007 Frequency Divider The most challenging block to operate from 2.5V. Given sizes of Q1-Q6, the size of Q7 & Q8 can be optimized. –important: inductor size, swing, latch pair size, current density.

10. © Sean Nicolson, BCTM 2006 © Sean Nicolson, 2007 Frequency Divider The most challenging block to operate from 2.5V. Given sizes of Q1-Q6, the size of Q7 & Q8 can be optimized. –important: inductor size, swing, latch pair size, current density.

11. © Sean Nicolson, BCTM 2006 © Sean Nicolson, 2007 SiGe Technology [Chevalier, 2006] 230/290GHz f T /f MAX SiGe HBT process Several “process splits” to find optimal HBT profile. 14mA/  m 2

12. © Sean Nicolson, BCTM 2006 © Sean Nicolson, 2007 LNA Measurements Fabricated & measured a 65nm CMOS LNA for comparison. –CMOS has more power supply variation (HBT feedback is stronger) –CMOS has low output resistance  higher bandwidth

13. © Sean Nicolson, BCTM 2006 © Sean Nicolson, 2007 LNA Measurements S21 vs. temp. shows 6dB variation up to 125C @ center band. –Again, upper band shows greater variation (less feedback). smaller change in gain here larger change in gain here

14. © Sean Nicolson, BCTM 2006 © Sean Nicolson, 2007 PA Measurements PAE = 15.7%, P SAT = +14 dBm, OP1dB = +11dBm

15. © Sean Nicolson, BCTM 2006 © Sean Nicolson, 2007 Mixer + IF Amplifier Measurements DSB noise figure of 13dB is pessimistic –harmonics from LO multiplier source, includes 3dB transformer loss. Min. NF current density at 73GHz (common base) is 5.5mA/  m 2.

16. © Sean Nicolson, BCTM 2006 © Sean Nicolson, 2007 Frequency Divider Measurements Operates up to 105.44GHz at 25°C and 97GHz at 100°C. –limited by power available from source.

17. © Sean Nicolson, BCTM 2006 © Sean Nicolson, 2007 Performance of Process Splits The best split is the reference, with the highest f MAX.

18. © Sean Nicolson, BCTM 2006 © Sean Nicolson, 2007 Conclusions and Future Work Excellent performance despite 2.5V supply. –SiGe divider 94GHz self-oscillation, and 75mW power consumption. –77GHz power amplifier PAE of 15.7% –+5dBm OP1dB from Mixer + IF amplifier –-101.5dBc/Hz at phase noise at 1MHz offset Transceiver currently in the fab –< 500mW power consumption (180mW for receiver, inc. VCO) –Contains only 33 HBTs (includes 16 in divider) + 2 MOS varactors.

19. © Sean Nicolson, BCTM 2006 © Sean Nicolson, 2007 Acknowledgements Ricardo Aroca and Katia Laskin for measurement help Jaro Pristupa and Eugenia Distefano for CAD/Network support STMicroelectronics & CITO for fabrication and funding

20. © Sean Nicolson, BCTM 2006 © Sean Nicolson, 2007 **Voltage-Controlled Oscillator Minimize phase noise, supply & temp dependence [2], [3]. –Small L B, differential tuning – C 1 + C BE >> C VAR, C 3 cancels C BC

21. © Sean Nicolson, BCTM 2006 © Sean Nicolson, 2007 VCO Measurements Phase noise better than -100dBc/Hz at 77GHz [2], [3].

22. © Sean Nicolson, BCTM 2006 © Sean Nicolson, 2007 More About Process Splits LNA S21 for several process splits. –Reference split looks the best.

23. © Sean Nicolson, BCTM 2006 © Sean Nicolson, 2007 More About Process Splits PA saturated S21 for several process splits –Again, the reference split looks the best.

24. © Sean Nicolson, BCTM 2006 © Sean Nicolson, 2007 More About Process Splits PA S11 for several process splits

25. © Sean Nicolson, BCTM 2006 © Sean Nicolson, 2007 Inductor Measurements Accurately simulated/modeled [Dickson, 2005] passives ( ±1pH).