A 2.5V, 77-GHz, Automotive Radar Chipset
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Transcript of A 2.5V, 77-GHz, Automotive Radar Chipset
© Sean Nicolson, BCTM 2006© Sean Nicolson, BCTM 2006© Sean Nicolson, 2007
A 2.5V, 77-GHz, AutomotiveA 2.5V, 77-GHz, AutomotiveRadar ChipsetRadar 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
WE2B-5
© Sean Nicolson, BCTM 2006© Sean Nicolson, BCTM 2006© Sean Nicolson, 2007
OutlineOutline• Motivation• Transceiver architecture• Circuit design & layout + some device insight• Fabrication technology• Measurements• Conclusions
© Sean Nicolson, BCTM 2006© Sean Nicolson, BCTM 2006© Sean Nicolson, 2007
ApplicationsApplications
• 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, BCTM 2006© Sean Nicolson, 2007
The Doppler Radar TransceiverThe 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
© Sean Nicolson, BCTM 2006© Sean Nicolson, BCTM 2006© Sean Nicolson, 2007
Low-noise AmplifierLow-noise Amplifier• 3-stage design, add R1 to de-Q the final stage.
• Noise & impedance matching including CPAD [Nicolson, 2006].
250m
1pF decoupling caps
k
ZCj
k
ZZ PADS
200
20
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© Sean Nicolson, BCTM 2006© Sean Nicolson, BCTM 2006© Sean Nicolson, 2007
Power AmplifierPower Amplifier• Primary goal: maximize PAE
– common source, class AB operation
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Down-conversion MixerDown-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, BCTM 2006© Sean Nicolson, 2007
Mixer + IF Amp LayoutMixer + IF Amp Layout• Layout is critical at 77GHz.
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Frequency DividerFrequency 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, BCTM 2006© Sean Nicolson, 2007
Frequency DividerFrequency 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, BCTM 2006© Sean Nicolson, 2007
SiGe Technology [Chevalier, 2006]SiGe Technology [Chevalier, 2006]• 230/290GHz fT/fMAX SiGe HBT process• Several “process splits” to find optimal HBT profile.
14mA/m2
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LNA MeasurementsLNA 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
mR
mmSg
Rg
fpeakNFET
mR
mmSVg
Rg
fpeakHBT
S
m
Sm
MAX
E
Tm
Em
MAX
200
1
2.11
@
5
14
8.31
@
2
© Sean Nicolson, BCTM 2006© Sean Nicolson, BCTM 2006© Sean Nicolson, 2007
LNA MeasurementsLNA 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, BCTM 2006© Sean Nicolson, 2007
PA MeasurementsPA Measurements• PAE = 15.7%, PSAT = +14 dBm, OP1dB = +11dBm
© Sean Nicolson, BCTM 2006© Sean Nicolson, BCTM 2006© Sean Nicolson, 2007
Mixer + IF Amplifier MeasurementsMixer + 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/m2.
© Sean Nicolson, BCTM 2006© Sean Nicolson, BCTM 2006© Sean Nicolson, 2007
Frequency Divider MeasurementsFrequency Divider Measurements• Operates up to 105.44GHz at 25°C and 97GHz at 100°C.
– limited by power available from source.
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Performance of Process SplitsPerformance of Process Splits• The best split is the reference, with the highest fMAX.
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Conclusions and Future WorkConclusions 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.
© Sean Nicolson, BCTM 2006© Sean Nicolson, BCTM 2006© Sean Nicolson, 2007
AcknowledgementsAcknowledgements
• 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, BCTM 2006© Sean Nicolson, 2007
**Voltage-Controlled Oscillator**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, BCTM 2006© Sean Nicolson, 2007
VCO MeasurementsVCO Measurements• Phase noise better than -100dBc/Hz at 77GHz [2], [3].
© Sean Nicolson, BCTM 2006© Sean Nicolson, BCTM 2006© Sean Nicolson, 2007
More About Process SplitsMore About Process Splits• LNA S21 for several process splits.
– Reference split looks the best.
© Sean Nicolson, BCTM 2006© Sean Nicolson, BCTM 2006© Sean Nicolson, 2007
More About Process SplitsMore About Process Splits• PA saturated S21 for several process splits
– Again, the reference split looks the best.
© Sean Nicolson, BCTM 2006© Sean Nicolson, BCTM 2006© Sean Nicolson, 2007
More About Process SplitsMore About Process Splits• PA S11 for several process splits
© Sean Nicolson, BCTM 2006© Sean Nicolson, BCTM 2006© Sean Nicolson, 2007
Inductor MeasurementsInductor Measurements• Accurately simulated/modeled [Dickson, 2005] passives ( ±1pH).