Transcript SIDECAR_LSST_CamMeet_11_08

Readout Electronics: SIDECAR ASIC
Hardware
SIDECAR ASIC
• Two sets of Control Electronics used: ARC and SIDECAR ASIC
• SIDECAR has great functionality; very powerful chip
• Challenge is to write assembly code to achieve functionality
SIDECAR FEATURES
36 Analog Inputs
20 Digital I/O Clocks
20 Output Biases
36 16 bit ADCs
36 12 bit ADCs
Taken from Loose et al. SPIE 2002
Taken from Loose et al. SPIE 2007
SIDECAR ASIC and H4RG
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SIDECAR ASIC set up at
Rochester Imaging Detector
Laboratory
All Clocks and Biases
probed during power-up and
regular operation
No Voltages above 3.3 V
going to detector
SIMPLE INTERFACE
HXRG
Hirose Connector
ASIC
JADE
SIDECAR ASIC attached to an H4RG and connected to
DELL Laptop with a USB cable
Computer
USB Cable
Have tested ASIC over 125 foot fiber/USB cable
External Electronics: Data from ASIC
CONFIG AND SCIENCE DATA
TO/FROM SIDECAR
JADE CARD
Spartan 3- FPGA
Xilinx Firmware written by Teledyne
=
EZ-USB FX2LP(TM) USB
Microcontroller
Quick USB DLL written by Bitwise
No Unix libraries or
source code
available for USB
microcontroller!
Only precompiled .dll
files containing
classes.
MICROSOFT COM FUNCTIONS
HalWrapper.dll written in C# and .NET
COMPUTER
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IDE Written by Teledyne
IDL Code or
Other interface
Setup used at ESO
Figure taken from Dorn et al. Evaluation of the Teledyne SIDECAR ASIC…’, SPIE 2006
- Cryogenic ASIC
sits inside dewar
- Standard LGA
socket packaging
provided by
Teledyne
JADE Card sits outside of dewar; JADE not used by SNAP team
Readout Electronics: SIDECAR ASIC
Firmware
Note: Fine details, likely not necessary for Corner
Raft Meeting
SIDECAR Video Inputs
• SIDECAR ASIC has
capacitively coupled
inputs
• Capacitive feedback
used for gain
• Leakage currents cause
voltage at node to rise
Amplification – S3 and S6 are open
Special sample and hold circuitry able to
sample voltage on Cfb as reference
– Very noticeable at room
temperature
– Must reset capacitors
periodically to prevent
large rise
– Problem: kTC noise
kTC Noise Removal
Reset PreAmps once per frame
Drift of voltage is apparent over
the frame
Reset PreAmps once per row
Different voltage due to kTC noise
appearing on caps is visible
from row to row
Reset PreAmps once per row with
kTC removal
Row to row noise is eliminated
SIDECAR ADC Averaging
• Noise of ADCs is ~2 ADU
• To beat it down, average input on multiple ADCs
• Input Routing Mux allows you to sample one input on 1-8 channels
Detector Video Output
Simplified Portion of
Routing Mux
Channel 7
Channel 6
Channel 5
Channel 4
Channel 3
Channel 2
Channel 1
Channel 0
ADC Averaging Results
• Noise goes down as 1/ NChannels as expected
• Only works if 4 or less outputs of HxRGs are used
• Second generation of SIDECAR ASIC expected to have lower noise
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