ICSO 2014 Tenerife CRYOGENIC AND RADIATION-HARD ASIC FOR INTERFACING LARGE FORMAT NIR/SWIR DETECTOR ARRAYS P.Gao, B.Dupont, B.Dierickx, E.Mueller, G.Verbruggen, S.Gielis, R.Valvekens, About us •Image sensors and periphery ASICs •Founded 2006 •Mechelen, Belgium •17 p (10 designers) Supplier of Custom designed Beyond “State of the Art” CMOS Image sensors and ASIC for Space, Scientific, Industrial and Medical applications 2 Outline • • • • • Motivation Architecture and building block design Design for Radiation hardness and Cryogenic temperature Test results Conclusions & future work 11/2/2014 ASIC for LF NIR/SWIR detector array 3 Outline • • • • • Motivation Architecture and building block design Design for Radiation hardness and Cryogenic temperature Test results Conclusions & future work 11/2/2014 ASIC for LF NIR/SWIR detector array 4 Why an ASIC ? To operate an IR imagers [Z.Zhao.SDA’05] Analog domain Signal conditioning Analog to digital converter Regulated power supply Bias voltage/current references 11/2/2014 Digital domain Digital control core Memory & Clock Data Communication ASIC for LF NIR/SWIR detector array 5 The ASIC This development aims at providing the community with a IR imager accompany ASIC • Tailored to imagers (especially IR sensor) – Easy to control – Simple to intergrade • Taking in consideration multiple IR detector manufacturers specificities •Wide operating temperature range (77k – room T) •Able to drive multi-sensor/array systems •Radiation hard – 1Mrad TID – 60MeVcm2 /mg SEU 11/2/2014 ASIC for LF NIR/SWIR detector array 6 Outline • • • • • Motivation Architecture and building block design Design for Radiation hardness and Cryogenic temperature Test results Conclusions& future work 11/2/2014 ASIC for LF NIR/SWIR detector array 7 Architecture 11/2/2014 ASIC for LF NIR/SWIR detector array 8 Analog section Bandgap T sensor 11/2/2014 ASIC for LF NIR/SWIR detector array 9 Supply • LDO – Programmable output • 1,3…3.4V – Stability: PM>60° – Output current 0-100mA • Bandgap – 1.2V – 77K-300K 11/2/2014 ASIC for LF NIR/SWIR detector array 10 Conversion channel • One ADC addressed 4 analog inputs in prototype ASIC • CDS – Bypassable • Preamplifier (PA) – Programmable gain from 0-30dB in 6dB step – Offset cancellation (8-bit) – Single to differential 11/2/2014 ASIC for LF NIR/SWIR detector array 11 ADC • 16-bit, 100kHz, fully differential SAR ADC – Hybrid feedback DAC – Low offset comparator auto zero • A calibration scheme is implemented 11/2/2014 ASIC for LF NIR/SWIR detector array 12 Digital section 11/2/2014 ASIC for LF NIR/SWIR detector array 13 Specifications Digital domain Master clock 0 – 200 MHz System level protocol 2 – 200 Mbit/s Space Wire ROIC digital control 32 ROIC monitoring and trigger inputs 8 Scheduler time granularity 10M updates/s Sequence nesting depth 8 ROIC programming channel 1 SPI 11/2/2014 ASIC for LF NIR/SWIR detector array 14 Outline • • • • • Motivation Architecture and building block design Design for Radiation hardness and Cryogenic temperature Test results Conclusions& future work 11/2/2014 ASIC for LF NIR/SWIR detector array 15 Radiation hardness: digital •Synthetized digital logic –DARE lib (IMEC & ESA) •0.18 um CMOS 1P6M •Digital cell with TID, SEU, SEL tolerance •Allows custom mixed-signal design –Redundancy •Hamming Codes •Parity check •Safe FSMs –Watchdog Timers 11/2/2014 ASIC for LF NIR/SWIR detector array 16 Radiation hardness: analog DARE has a limited subset of analog component. Caeleste developed its own radhard cells •Analog and High Voltage logic standard cells •Full custom tactical cells – – – – – – Analog & mixed mode TID & TnID hardness SEL hardness SEU hardness without TR <20% increased Cin and power <50% area increase 11/2/2014 ASIC for LF NIR/SWIR detector array Normal Caeleste mixed mode Caeleste RH 17 Design for low temperature •Synthetized digital logic: – A derating of speed, power, etc. of the library – SRAM •Analog custom design: – Active component modeling – Component selection 11/2/2014 ASIC for LF NIR/SWIR detector array 18 Cryogenic digital design The DARE library has never been used at 77K before •Faster but risk for set-up and hold time violation. – Adapted models based on characterization at 218K •SRAM has not been validated before – Backup registers 11/2/2014 ASIC for LF NIR/SWIR detector array 19 Cryogenic analog design • MOSFET modeling – Vth: increase – Mobility: increase – MOS switch: low Ron PMOS: 0.75-0.97 NMOS: 0.68-0.91 Transistor Vt • Passive components – Highly doped non silicide poly Resistor for stability – MIM capacitors • Rely on ratios not absolutely values 11/2/2014 ASIC for LF NIR/SWIR detector array 20 Outline • • • • • Motivation Architecture and building blocks design Design for Radiation hardness and Cryogenic temperature Test results Conclusions 11/2/2014 ASIC for LF NIR/SWIR detector array 21 Test setup Unified design for: RT board CT board + Precision DAC board Digital Controller RT board ASIC COB Analog test board Base plate + CT board 11/2/2014 ASIC for LF NIR/SWIR detector array 22 Bandgap and temperature sensor Bandgap measuement T-sensor measurement 1,35 1,0 0,9 T coefficient< 1mV/K 0,8 output voltage (V) output valtage (V) 1,3 1,25 1,2 1,15 T coefficient: 3mV/K 0,7 0,6 0,5 0,4 0,3 0,2 1,1 0,1 1,05 0 50 100 150 200 250 300 350 0,0 70 120 Temperature (K) 11/2/2014 ASIC for LF NIR/SWIR detector array 170 220 Temperature (K) 270 320 23 Reference and Biases 10-bit BIAS0 DNL 0,04 0,03 DNL(LSB) 0,02 0,01 0 -0,01 0 200 400 600 800 1000 600 800 1000 -0,02 -0,03 -0,04 Input code BIAS0 INL 0,6 INL(LSB) 0,4 0,2 0 0 200 400 -0,2 -0,4 Input code 11/2/2014 ASIC for LF NIR/SWIR detector array 24 R monitor • On chip SC current source. – R range 10k – 70k ohm Measured output voltage with 2MHz clock 11/2/2014 ASIC for LF NIR/SWIR detector array 25 16-bit SAR ADC INL DNL •INL DNL problem : –Root cause is a AC coupling in the M5 layout: 2 fF cross-coupling M4 11/2/2014 ASIC for LF NIR/SWIR detector array 26 ADC INL DNL • ADC INL DNL problem analysis 11/2/2014 ASIC for LF NIR/SWIR detector array 27 ADC INL DNL • ADC INL DNL @ 50KHz fs 11/2/2014 ASIC for LF NIR/SWIR detector array 28 Measurement summary Measurement result @ room T Specs Supply voltage Total current consumption Regulator PSRR Regulator I out Output impedance LDO output Analog rail to rail voltage Reference DAC INL Reference DAC DNL ADC noise ADC fs ADC INL ADC DNL Monitor resistance range Number of digital outputs/ inputs Digital output clock speed Serial interface speed SpaceWire bit rate ASIC start-up time Temperature range 11/2/2014 @ cryogenic T 3.5-3.6V 53mA 60.5mA > 40dB > 40mA < 1Ω 1.3-3.4 V 3.3 V 0.7LSB 0.06LSB 2.5LSB 1LSB 0.04LSB 2.1LSB 50, 100, 200KHz 78LSB (15LSB@50KHz) 76LSB (16LSB@50KHz) 10KΩ -70KΩ 32 / 8 0-10 MHz 50KHz-50MHz 0-200 Mbps ≤50us 77K-room T (Measured) ASIC for LF NIR/SWIR detector array 29 Outline • • • • • Motivation Architecture and building block design Design for Radiation hardness and Cryogenic temperature Test results Conclusions& future work 11/2/2014 ASIC for LF NIR/SWIR detector array 30 Conclusions • Prototype accompany ASIC for (IR) detector arrays which provide all functionalities has been demonstrated – • Full function has been proven from cryogenic (77K) to room temperature – – • All Caeleste custom designed cells Digital cells in DARE Lib. Including SRAM Highly flexible for ROICs – – • ADC problem founded and will solve in next iteration Highly programmable sequencer Wide programmability and large dynamic ranges in analog acquisition chain Beyond IR imagers 11/2/2014 ASIC for LF NIR/SWIR detector array 31 Next steps ? • Larger ASIC with multiple channels (32 to 64) • Faster ADCs is now developing at Caeleste (up to 12MS/s with reduced resolution) • Irradiation testing • More discussion with instrument builders and IR sensor manufacturers for further enhancements 11/2/2014 ASIC for LF NIR/SWIR detector array 32 Thank you! 11/2/2014 ASIC for LF NIR/SWIR detector array 33
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