Transcript WE2B-5 A 2.5V, 77-GHz, Automotive Radar Chipset Sean T. Nicolson1, Keith A. Tang1, Kenneth H.K.

WE2B-5
A 2.5V, 77-GHz, Automotive
Radar Chipset
Sean T. Nicolson1, Keith A. Tang1, Kenneth H.K. Yau1, Pascal
Chevalier2, Bernard Sautreuil2, and Sorin P. Voinigescu1
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
© Sean©Nicolson,
BCTM 2006
Sean Nicolson,
2007
Outline
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Motivation
Transceiver architecture
Circuit design & layout + some device insight
Fabrication technology
Measurements
Conclusions
© 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.
© Sean©Nicolson,
BCTM 2006
Sean Nicolson,
2007
The Doppler Radar Transceiver
• Doppler transceiver block diagram
Modulation
VCO
freq. div.
PA
To PLL
Antennae
IF amp
LNA
Mixer
• Development steps
– Design & test circuit blocks + optimize HBT for circuit performance
– Integrate circuit blocks into transceiver
– Duplicate to form arrays
© Sean©Nicolson,
BCTM 2006
Sean Nicolson,
2007
Low-noise Amplifier
• 3-stage design, add R1 to de-Q the final stage.
250mm
1pF decoupling caps
• Noise & impedance matching including CPAD [Nicolson, 2006].
Z0
CPADZ 02
ZS 
j
k
k
k  1 
2
2
C PAD
Z 02
LE ( new)
© Sean©Nicolson,
BCTM 2006
Sean Nicolson,
2007
Z0

kT
g m( new)  kg m
Power Amplifier
• Primary goal: maximize PAE
– common source, class AB operation
© 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 (1.25VPP/side)
– 12.5mW PDC
input
© Sean©Nicolson,
BCTM 2006
Sean Nicolson,
2007
Mixer + IF Amp Layout
• Layout is critical at 77GHz.
© 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.
© 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.
© Sean©Nicolson,
BCTM 2006
Sean Nicolson,
2007
SiGe Technology [Chevalier, 2006]
• 230/290GHz fT/fMAX SiGe HBT process
• Several “process splits” to find optimal HBT profile.
14mA/mm2
© 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
HBT @ peak f MAX
1  g m RE  3.8
g m  14 VT m S mm
RE  5mm 2
NFET @ peak f MAX
1  g m RS  1.2
g m  1 m S mm
RS  200mm
© 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
© Sean©Nicolson,
BCTM 2006
Sean Nicolson,
2007
PA Measurements
• PAE = 15.7%, PSAT = +14 dBm, OP1dB = +11dBm
© 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/mm2.
© 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.
© Sean©Nicolson,
BCTM 2006
Sean Nicolson,
2007
Performance of Process Splits
• The best split is the reference, with the highest fMAX.
© Sean©Nicolson,
BCTM 2006
Sean Nicolson,
2007
Conclusions and Future Work
• Excellent performance despite 2.5V supply.
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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.
© 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
© Sean©Nicolson,
BCTM 2006
Sean Nicolson,
2007
**Voltage-Controlled Oscillator
• Minimize phase noise, supply & temp dependence [2], [3].
– Small LB, differential tuning
– C1 + CBE >> CVAR, C3 cancels CBC
© Sean©Nicolson,
BCTM 2006
Sean Nicolson,
2007
VCO Measurements
• Phase noise better than -100dBc/Hz at 77GHz [2], [3].
© Sean©Nicolson,
BCTM 2006
Sean Nicolson,
2007
More About Process Splits
• LNA S21 for several process splits.
– Reference split looks the best.
© 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.
© Sean©Nicolson,
BCTM 2006
Sean Nicolson,
2007
More About Process Splits
• PA S11 for several process splits
© Sean©Nicolson,
BCTM 2006
Sean Nicolson,
2007
Inductor Measurements
• Accurately simulated/modeled [Dickson, 2005] passives ( ±1pH).
© Sean©Nicolson,
BCTM 2006
Sean Nicolson,
2007