characterization of 1.2ghz phase locked loops and voltage controlled oscillators in a total dose...

Characterization of 1.2GHz PhaseCharacterization of 1.2GHz PhaseLocked Loops and Voltage Controlled Locked Loops and Voltage Controlled Oscillators in a Total Dose Radiation Oscillators in a Total Dose Radiation

EnvironmentEnvironment

Martin Vandepas, Kerem Ok, Anantha Nag Nemmani, Merrick Martin Vandepas, Kerem Ok, Anantha Nag Nemmani, Merrick Brownlee, Kartikeya Mayaram, Un-Ku MoonBrownlee, Kartikeya Mayaram, Un-Ku Moon

Oregon State UniversityOregon State UniversityDepartment of Electrical and Computer EngineeringDepartment of Electrical and Computer Engineering

MAPLD 2005MAPLD 2005

September 7-9, 2005September 7-9, 2005

2/27Vandepas MAPLD 2005/230

OutlineOutline

• Test chip descriptionTest chip description

• Radiation test setupRadiation test setup

• ResultsResults

• ConclusionConclusion


Test Chip (Honeywell MOI-5)Test Chip (Honeywell MOI-5)

• PLLsPLLs– LC oscillator PLLLC oscillator PLL– Ring oscillator PLLRing oscillator PLL

• LC oscillators LC oscillators – NMOS current sourceNMOS current source– PMOS current sourcePMOS current source– Complementary current sourceComplementary current source

• Ring oscillatorsRing oscillators– Maneatis delay cellManeatis delay cell– Linear-load modified Maneatis delay cellLinear-load modified Maneatis delay cell– Lee-Kim delay cellLee-Kim delay cell


Test Chip Die PhotoTest Chip Die Photo

LC oscillatorsLC oscillators

RingRingoscillatorsoscillatorsLC PLLLC PLL

Ring PLLRing PLL


Prototype PLLsPrototype PLLs

• Ring-VCO PLL• Programmable

“N” & “ICP”

• LC-VCO PLL• Programmable

“N” & “ICP”


Prototype PLL SummaryPrototype PLL Summary

Ring-oscillator PLLRing-oscillator PLL LC-tank PLLLC-tank PLL

VCO tuning rangeVCO tuning range 0.43GHz – 1.12GHz0.43GHz – 1.12GHz 1.2GHz – 1.45GHz 1.2GHz – 1.45GHz (simulated)(simulated)

Power consumptionPower consumption 26mW 26mW @ 800MHz@ 800MHz

35 mW 35 mW @ 1.2GHz@ 1.2GHz

Layout areaLayout area 600mm 600mm ×× 500mm 500mm 1000mm 1000mm ×× 1100mm 1100mm

ProcessProcess Honeywell MOI-5 0.35Honeywell MOI-5 0.35µµm processm process

Total pin countTotal pin count 25 (8 inputs, 7 outputs, 10 power)25 (8 inputs, 7 outputs, 10 power)


Prototype LC VCOsPrototype LC VCOs

NMOS current source

PMOS current source

Complementary current sources


Prototype Ring OscillatorsPrototype Ring Oscillators

Maneatis cell Lee/Kim cellLinear-load

• Maneatis delay cell: symmetric & linear loadsManeatis delay cell: symmetric & linear loads• Lee/Kim delay cell: Lee/Kim delay cell: traditionaltraditional & signal-delay- & signal-delay-optimizedoptimized

layoutlayout• Body ties in SOI: with Body ties in SOI: with body tiesbody ties & without ( & without (floatingfloating body) body)


Radiation Test SetupRadiation Test Setup

• Two testsTwo tests– 500krad(SiO500krad(SiO22) at a dose rate of 500 rad/sec) at a dose rate of 500 rad/sec

• One exposureOne exposure• Characterize the oscillators before and after Characterize the oscillators before and after

the dosethe dose

– 25krad(SiO25krad(SiO22) to 6.4Mrad(SiO) to 6.4Mrad(SiO22) doubling ) doubling

dosage each stepdosage each step• Tested current and lock range of ring PLL vs. Tested current and lock range of ring PLL vs.

total radiation dosetotal radiation dose• Quantify effect of annealing 35 days after Quantify effect of annealing 35 days after

radiation at room temperatureradiation at room temperature


Radiation Equipment at AFRLRadiation Equipment at AFRL

• Phillips low energy X-Ray (LEXR) tubePhillips low energy X-Ray (LEXR) tube– Shown with cryo chamber (not used)Shown with cryo chamber (not used)

• Chip irradiated directly with IC lid removedChip irradiated directly with IC lid removed• All circuits biased except buffersAll circuits biased except buffers


First TestFirst Test

• Current consumption about constant Current consumption about constant throughout irradiationthroughout irradiation– Suggests leakage current is not significant Suggests leakage current is not significant

for the given dosefor the given dose

• One notable observationOne notable observation– Shifted tuning range for ring-based Shifted tuning range for ring-based

oscillatorsoscillators

• Annealing until measurement of VCOsAnnealing until measurement of VCOs– Dependence on process makes Dependence on process makes

characterization of annealing difficultcharacterization of annealing difficult


PMOS Source LC VCOPMOS Source LC VCO

-1.5 -1 -0.5 0 0.5 1 1.51100

1200

1300

1400

1500

1600

1700

Control Voltage (V)

Fre

qu

en

cy

(M

Hz)

Pre-rad BodyPost-rad BodyPre-rad FloatPost-rad FloatSim


NMOS Source LC VCONMOS Source LC VCO

0 0.5 1 1.5 2 2.5 31100

1150

1200

1250

1300

1350

1400

1450

1500

1550

1600

1650

Control Voltage (V)

Fre

qu

en

cy

(M

Hz)



Complementary Source LC VCOComplementary Source LC VCO

0 0.5 1 1.5 2 2.51100

1200

1300

1400

1500

1600

1700

Control Voltage (V)

Fre

qu

en

cy

(M

Hz)



Lee/Kim Traditional LayoutLee/Kim Traditional Layout

0 0.5 1 1.5 2 2.5300

400

500

600

700

800

900

1000

1100

1200

Control Voltage (V)

Fre

qu

en

cy

(M

Hz)



Lee/Kim Signal-Path-Optimized Lee/Kim Signal-Path-Optimized LayoutLayout

0 0.5 1 1.5 2 2.5400

600

800

1000

1200

1400

1600

1800

Control Voltage (V)

Fre

qu

en

cy

(M

Hz)



Linear-Load Modified-Maneatis Linear-Load Modified-Maneatis OscillatorOscillator

0 0.5 1 1.5 2 2.5900

1000

1100

1200

1300

1400

1500

1600

1700

1800

1900

2000

Control Voltage (V)

Fre

qu

en

cy

(M

Hz)



Period Jitter: Period Jitter: LCLC VCOs VCOsCHIP 1 CHIP 1 PREPRE-Radiation-Radiation

RMS RMS (ps)(ps)

Peak-to-Peak-to-peak (ps)peak (ps)

Power Power (mW)(mW)

Frequency Frequency (MHz)(MHz)

PMOS Source PMOS Source Body TiedBody Tied

2.752.75 18.9018.90 29.429.4 15001500

PMOS Source PMOS Source Floating BodyFloating Body

3.003.00 21.7221.72 28.128.1 15001500

NMOS Source NMOS Source Body TiedBody Tied

3.143.14 21.7321.73 28.328.3 15001500

NMOS Source NMOS Source Floating BodyFloating Body

-- -- -- --

Complementary Complementary Body TiedBody Tied

3.303.30 22.5822.58 46.1346.13 15001500

Complementary Complementary Floating BodyFloating Body

-- -- -- --


CHIP 1 CHIP 1 PREPRE-Radiation-Radiation

RMS RMS (ps)(ps)




Lee/Kim Traditional Lee/Kim Traditional Body TiedBody Tied

2.592.59 16.7916.79 26.9026.90 800800

Lee/Kim Traditional Lee/Kim Traditional Floating BodyFloating Body

2.582.58 16.4916.49 26.4026.40 800800

Lee/Kim Optimized Lee/Kim Optimized Body TiedBody Tied

2.402.40 15.8615.86 23.4323.43 800800

Lee/Kim Optimized Lee/Kim Optimized Floating BodyFloating Body

2.682.68 17.8017.80 21.4521.45 800800

Linear-Load Linear-Load (Maneatis) Body (Maneatis) Body TiedTied

2.792.79 19.5219.52 102102 12001200

Linear-Load Linear-Load (Maneatis) Floating(Maneatis) Floating

3.383.38 22.3122.31 102102 12001200

Period Jitter: Period Jitter: RingRing VCOs VCOs


Period Jitter: Period Jitter: LCLC VCOs VCOsCHIP 2 CHIP 2 POSTPOST-Radiation-Radiation

RMS RMS (ps)(ps)




PMOS Source PMOS Source Body TiedBody Tied

3.253.25 21.0821.08 26.6726.67 15001500

PMOS Source PMOS Source Floating BodyFloating Body

3.053.05 21.0821.08 26.9026.90 15001500

NMOS Source NMOS Source Body TiedBody Tied

3.303.30 26.1326.13 27.9227.92 15001500

NMOS Source NMOS Source Floating BodyFloating Body

3.073.07 20.0020.00 27.6927.69 15001500

Complementary Complementary Body TiedBody Tied

3.293.29 22.3422.34 37.9537.95 15001500

Complementary Complementary Floating BodyFloating Body

2.942.94 17.8917.89 37.9537.95 15001500


CHIP 2 CHIP 2 POSTPOST-Radiation-Radiation

RMS RMS (ps)(ps)




Lee/Kim Traditional Lee/Kim Traditional Body TiedBody Tied

3.133.13 21.9221.92 26.4026.40 800800

Lee/Kim Traditional Lee/Kim Traditional Floating BodyFloating Body

2.742.74 17.8017.80 26.7026.70 800800

Lee/Kim Symmetric Lee/Kim Symmetric Body TiedBody Tied

2.532.53 18.0018.00 22.7722.77 800800

Lee/Kim Symmetric Lee/Kim Symmetric Floating BodyFloating Body

2.912.91 19.6819.68 21.7821.78 800800

Linear-Load Linear-Load (Maneatis) Body Tied(Maneatis) Body Tied

5.275.27 37.0337.03 100100 12001200

Linear-Load Linear-Load (Maneatis) Floating(Maneatis) Floating

6.016.01 40.7040.70 9999 12001200

Period Jitter: Period Jitter: RingRing VCOs VCOs


Second Test – Ring PLLSecond Test – Ring PLL

• Circuit current Circuit current vs. total dosevs. total dose

• Very little Very little annealingannealing

105

106

58

59

60

61

62

63

64

65

Total Circuit Board Bias Current @ 45MHz FREF

Total Radiation Dose (Rad SiO2)

Curr

ent

(mA)

After 35 days annealing


Second Test – Ring PLLSecond Test – Ring PLL

• Lock range vs. Lock range vs. total dosetotal dose

• Still locks at Still locks at 6.2MRad(SiO6.2MRad(SiO22))

• Gaps are due Gaps are due to test setupto test setup

105

106

400

500

600

700

800

900

1000

1100

1200

Lock Range

Total Radiation Dose (Rad SiO2)

Frequency

(M

Hz)

After 35 days annealing


Total Dose Effect on PLLsTotal Dose Effect on PLLs

• Digital blocksDigital blocks– Can tolerate large shifts in threshold voltagesCan tolerate large shifts in threshold voltages– Immune to large doses of radiationImmune to large doses of radiation– Continue functioning until transistors cannot be Continue functioning until transistors cannot be

turned onturned on

• Charge Pump and Loop FilterCharge Pump and Loop Filter– Performance degradationPerformance degradation– Current mismatch & leakageCurrent mismatch & leakage– Eventual functional failureEventual functional failure

• VCOVCO– Tuning curve (fTuning curve (fOSCOSC, K, KVCOVCO) changes) changes


Total Dose HardeningTotal Dose Hardening

• Self calibration/tuningSelf calibration/tuning• Analog tuning mechanisms are Analog tuning mechanisms are

susceptible to total dosesusceptible to total dose• Digital blocks can inherently resist large Digital blocks can inherently resist large

doses of radiation before functional doses of radiation before functional failurefailure

• All digital PLLsAll digital PLLs ideal for total dosage ideal for total dosage hardeninghardening

• Architectures with loop parameters Architectures with loop parameters independent of environmentindependent of environment


ConclusionsConclusions

• Analog PLL’s can be sensitive to total Analog PLL’s can be sensitive to total dose radiationdose radiation

• Designing with threshold shifts in mind Designing with threshold shifts in mind can harden themcan harden them

• New all-digital PLL techniques may New all-digital PLL techniques may present total dose hardened by design present total dose hardened by design PLLsPLLs


AcknowledgmentAcknowledgment

• We would like to thank Ken Merkel, We would like to thank Ken Merkel, Steve Clark, Dave Alexander, and Bill Steve Clark, Dave Alexander, and Bill Kemp of the Air Force Research Lab in Kemp of the Air Force Research Lab in Albuquerque, NM for their direct Albuquerque, NM for their direct support of the radiation testingsupport of the radiation testing

• Thanks to AFRL for sponsoring this Thanks to AFRL for sponsoring this projectproject

characterization of 1.2ghz phase locked loops and voltage controlled oscillators in a total dose...

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