© sean nicolson, bctm 2006 © sean nicolson, 2007 a 2.5v, 77-ghz, automotive radar chipset sean t....

© 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


OutlineOutline• Motivation• Transceiver architecture• Circuit design & layout + some device insight• Fabrication technology• Measurements• Conclusions


ApplicationsApplications

• W-band applications: 77GHz auto radar, 94GHz weather radar, imaging, data communications

• All applications require a W-band radio transceiver.


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


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

221 ZCk PADT

newE k

ZL

0

)( mnewm kgg )(


Power AmplifierPower Amplifier• Primary goal: maximize PAE

– common source, class AB operation


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


Mixer + IF Amp LayoutMixer + IF Amp Layout• Layout is critical at 77GHz.


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.


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


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


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


PA MeasurementsPA Measurements• PAE = 15.7%, PSAT = +14 dBm, OP1dB = +11dBm


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.


Frequency Divider MeasurementsFrequency Divider Measurements• Operates up to 105.44GHz at 25°C and 97GHz at 100°C.

– limited by power available from source.


Performance of Process SplitsPerformance of Process Splits• The best split is the reference, with the highest fMAX.


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.


AcknowledgementsAcknowledgements

• Ricardo Aroca and Katia Laskin for measurement help• Jaro Pristupa and Eugenia Distefano for CAD/Network support• STMicroelectronics & CITO for fabrication and funding


**Voltage-Controlled Oscillator**Voltage-Controlled Oscillator• Minimize phase noise, supply & temp dependence [2], [3].

– Small LB, differential tuning– C1 + CBE >> CVAR, C3 cancels CBC


VCO MeasurementsVCO Measurements• Phase noise better than -100dBc/Hz at 77GHz [2], [3].


More About Process SplitsMore About Process Splits• LNA S21 for several process splits.

– Reference split looks the best.


More About Process SplitsMore About Process Splits• PA saturated S21 for several process splits

– Again, the reference split looks the best.


More About Process SplitsMore About Process Splits• PA S11 for several process splits


Inductor MeasurementsInductor Measurements• Accurately simulated/modeled [Dickson, 2005] passives ( ±1pH).

© sean nicolson, bctm 2006 © sean nicolson, 2007 a 2.5v, 77-ghz, automotive radar chipset sean t....

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