Why we dare to go without DARE (library) Innovation for life
TNO is active in five core areas Quality of Life Defence, Security & Safety Science & Industry Built Environment & Geosciences Information & Communication Technology 2
Activities in Opto-Mechanical Instrumentation for Space Applications Scientific payload instrumentation, such as spectrometers S59 UV stellar spectrometer ISO Short wave Spectrometer (5-15 microns) Herschel HIFI design and production support Herschel HIFI cryogenic alignment camera system Earth-observation payload instrumentation & calibration GOME, SCIAMACHY, OMI design, production & calibration Diffuser design, production and calibration Optical Ground Support Equipment (GOME, SCIA, IASI) Multi-spectral imaging spectrometer (Earthcare) Precision Mechanics Refocussing mechanisms for MSG Optical Delay-Lines (Darwin technology development) Achromatic Phase Shifters, Nulling technology (Darwin) GAIA basic angle monitoring; Wave Front Sensor; Test eqpt Avionics Equipment and Other business Sun sensors Precision Optical Metrology sensors for Formation Flying Fibre-Bragg grating for in-situ measurement of stress, deformation etc 3
TNO s current portfolio Existing Products Current developments - SOTS Specials and mission specific sensors 4
Start of the miniaturisation within Microned Autonomous micro-digital sunsensor Autonomous power Wireless link MEMS based 5
Main deliverable APS + chip Single chip sunsensor Optimised for low power TSMC 0.18 micron process Last spin-out 5 th May Chips received 23 th of june Standard design library Several circuit design modifications to avoid SEL and SEU related issues. 6
Key personel Albert Theuwissen Ning Xie 7
Key personel Murat Durkut Johan Leijtens Henk Hakkesteegt Henk Jansen 8
Total dose radiation tolerance 1,0 0.18 micron CMOS TSMC 0,9 0,8 Pixels tested up to 100 krad 0,7 0,6 No significant impact observed 0,5 0,4 Using DARE library would 0,3 0,2 increase power consumption by 0,1 0,0 factor of 2 Low power was the main requirement 20krad is sufficient for majority of applications For small systems extra shielding has less impact Quantum Efficiency P in n e d P h o to d io d e a re a /P ix e l: 5 3 (µ m 2 ) P ix e l N u m b e r: 5 5 0 0 T o ta l P in n e d P h o to d io d e A re a : 2 9 1 5 0 0 (µ m 2 ) In te g ra tio n T im e : 0,0 3 (s e c ) B e fo r e R a d ia tio n 8 6 k ra d 1 0 6 k r a d 2 0 0 3 0 0 4 0 0 5 0 0 6 0 0 7 0 0 8 0 0 9 0 0 1 0 0 0 1 1 0 0 1 2 0 0 W a v e le n g th (n m ) No DARE library was used 9
Radiation tolerance tested with gated pixel total ionizing dose (TID) level of 31krad, 86krad, 106krad, 109krad and 137krad with an average energy of 46.2keV No significant decrease in quantum efficiency No appreciable increase in dark current for 30krad Number of Pixels 1 0 0 0 1 0 0 1 0 1 B e fo re R a d ia tio n 3 1 k ra d 1 0 9 k ra d T G T ra n s is to r is o ff Ref: 0 2 0 4 0 D a rk R a n d o m N o is e (D N ) 10
Increased darkcurrent not significant. Significantly lower then threshold Noise on reading less then 0.004 degrees for ±47 degree system 11
Single Event Latch-up in CMOS Parasitic SCR (through substrate) SEL if gain >1 SEU if gain <1 Latch up can destroy the circuit N.B. Significant current can only flow if both N+ and P+ terminals are connected to low impedance, and substrate resistance is high enough 12
SEL hardened pixel design Winner takes all 3T pixel design Parasitic SCR through NMOS reset transistor and PMOS source follower Reduced QE due to N well for PMOS transistor n + n + n - p - 3.3 V N.B. Reduced QE not important for this application, because there is an abundance of light. 13
SEL hardened winner takes all pixel design 3.3 V All PMOS design PMOS reset transistor is not significantly reducing QE any further Extra ground connection per pixel to reduce substrate resistance.(decreases the effect of any SEU) n + 1.8 V n + n - p - 3.3 V No SCR no SEL n + p - 14
Ten pixel pin-hole No false detection of the sunspot due to bad pixels or SEU Replace affected pixels by the average of neighbouring pixels Automatic compensation of SEE 15
Single cycle acquisition through winner takes all hardware. No forbidden states in the internal state machines. Hard wired configuration straps Automatic switchback to acquisition mode at SEU Loss of accuracy for a single cycle due to SEU is the worst consequence 16
Conclusions Power consumption is our main driver Total dose radiation tolerance is sufficient for most sunsensor applications SEL/SEU effects are deemed more critical and tackled through several design decisions (DARE) 17
That s why we dare to go without DARE libraries But we don t dare to go without DARE 18 Thank you for your attention. For further information Johan Leijtens +31 15 269 2191 Johan.leijtens@tno.nl