1. LSST Electronics Review – BNL, January 25-26 20121 LSST Electronics Review BNL January 25-26 2012 Raft Electronics Overview R. Van Berg Electronics Mini-Review January 25 th, 2012

2. LSST Electronics Review – BNL, January 25-26 20122 Outline – LSST Raft Electronics Driving Requirements Raft Functionality FEB Overview ASIC Functions Raft Logical Organization Back End Functions Back End Logical Organization Institutional Responsibilities

3. LSST Electronics Review – BNL, January 25-26 20123 Driving Requirements Noise (10 e-) –ASPIC design –Diff amp and ADC choice –Integration time (vs. readout time) Crosstalk (0.05%) –ASPIC design –FEB design –Cable design –Power distribution Readout time (2 sec) –Integration time (vs. noise) –ADC speed –DAQ speed Dynamic range (> 90,000 e-) –ADC range –Noise Space –Fit in shadow of focal plane –Front and BE electronics in cryostat –Small cable plant to feed through flange Thermal –Low temperature differences across boards Power (as low as possible) –Cryo cooling for FEB –Cold cooling for RCC Environmental contamination –Low outgassing (to protect CCD surface) Repairability –Modularity (rafts vs. unitary FP) –Raft level power, control, data flow Reliability –Conservative design –Extensive testing –High quality materials, parts

4. LSST Electronics Review – BNL, January 25-26 20124 Cryostat Main Chamber Housing is the Primary Integrating Structure of the Camera FUNCTIONALITY: –Low mass aluminum vacuum vessel & rigid support ring –Stiff Si Carbide Grid to support & stabilize focal plane array – Cryo-plate, cold-plate & shrouds to stabilize thermal environment of Grid, the sensors and electronics –Getter pumping to reduce condensates on focal plane Cryo Feedthru ( 3.07.07) Cold Plate (3.07.03) Grid (3.07.05) Focal plane Raft Sensor Array Cryo shrouds ( 3.07.03) Back end crate Front end crate Housing ( 3.07.02) Backend Vacuum plate ( 3.07.07) Getter Pump (3.07.06) Support Ring (3.07.02) L3 & L3 Flange Cryo Plate ( 3.07.03)

5. LSST Electronics Review – BNL, January 25-26 20125 Raft Functionality – Front End Cage + Raft Control Crate ASPIC –Preamp –DSI CABAC –Clock Drive –Bias drive (OD, RD, etc.) Current Source –OS sink Power Regulators for ASICs 3.2 Gb/s I/O 18 Bit 1MS/s ASPIC ADC FPGA CABAC Diff Amp Diff Amp FEB – 24 Channels Full Custom ASICs BEB – 24 Channels Commercial parts RCM – 144 Channels Commercial parts i i CCDCCD CCDCCD CCDCCD Diff Amps –ADC Drive –Offset ADCs –18 bit for video –12+ bit for monitor* Low Level Clock Drive DACs and V Regulators –Clock levels –Biases FPGA –Generate timing phases –Absorb ADC data –Serialize and Xmit ADC data –Configure and control SPI bus devices DACs 6X 1X * Not yet implemented

6. LSST Electronics Review – BNL, January 25-26 20126 3.2 Gb/s I/O 18 Bit 1MS/s Raft Functionality ASPIC ADC FPGA CABAC Diff Amp Diff Amp FEB – 24 Channels Full Custom ASICs BEB – 24 Channels Commercial parts RCM – 144 Channels Commercial parts Front End Cage -100C Raft Control Crate -40C i i CCDCCD CCDCCD CCDCCD DACs

7. LSST Electronics Review – BNL, January 25-26 20127 Front End Board – Six per Front End Cage All Analog processing –Preamplification –Dual Slope Integration Clock Drive Bias generation for CCDs 10 Layers –Shielded transmission lines to back end –Multiple GND planes –Lo capacity inputs to ASPIC –All command lines LVDS –Separate LDO analog regulators for ASPIC and SCC chips High thermal conductivity to edge bars –Thermal simulations show only a few deg rise across board – need to verify High rel. connectors – nano to CCD and micro to BEB 24 Current sources (I S ) 3 ASPICs (8 channels each) 6 SCCs (3 serial clocks, 3 parallel) Goes to 3 CABACs next version CCD connectors (3) Bias and control Video output

8. LSST Electronics Review – BNL, January 25-26 20128 Analog signal processing of CCD :ASPIC – 3 Per FEB  Techno : CMOS 0.35µ/5V  Vendor : AMS  Packages :  CQFP100  CQFN100  8 DSI channels  Techno : CMOS 0.35µ/5V  Vendor : AMS  Packages :  CQFP100  CQFN100  8 DSI channels  3 programmable input amplifier gains : 2.5 – 5 – 7.5  to deal with CCD gain spread.  3 integration time constants : 500ns – 1µs – 1.5µs  to deal with CCD readout frequency.  Idle mode : DC current reduction by a factor of 1000 baseline : { gain 5 & 500ns integration time} Integrators Input amp Single ended to diff Thermal PAD CQFN pack.

9. LSST Electronics Review – BNL, January 25-26 20129 Read Out Method : Dual Slope Integration CCD Reset ASPIC Reset CCD Output Integration Time Tint Isolation Time ADC S/H Dual Slope Integration sequence One of the 2 differential channel output Ramp Down (integrate noise) Ramp Up (integrate signal + noise)

10. LSST Electronics Review – BNL, January 25-26 201210 CABAC : clock and biases asic for CCD 10 IΦ0IΦ1IΦ2IΦ3IΦ0IΦ1IΦ2IΦ3 IΦ3IΦ3 CABAC Serial link RO EXT Clocks OD Biases Muxout Clock timing

11. LSST Electronics Review – BNL, January 25-26 201211 Logical Organization – a short RTM primer…. Each Raft has 9 sensors –Each sensor has 16 outputs – 8+8 Each Raft has 6 FEBs Each FEB has 24 channels –Two FEBs handle 3 CCDs 3 x 8 outputs = 24 channels 3 ASPICs per FEB Serial clocks from both FEBs Parallel clocks from one FEB  Two types of FEB (CABAC will simplify) –One BEB per FEB – all BEBs identical Geographical coding selects clock type –One RCM per raft – 144 Mpixels, 3.2Gbps output 6 BEBs 6 FEBs 9 CCDs 1 RCM Front End Cage FEC Raft Tower Module RTM Raft Control Crate RCC

12. LSST Electronics Review – BNL, January 25-26 201212 RCC Functionality - BEB Video Digitization –18 Bit, 1Msps precision ADCs –Run at ~ 550 kpixels/sec to meet 2 second readout requirement –Differential output from ASPIC into discrete diff amp to drive ADC (high C load) ADC diff input range from +5V to -5V  18 bits ASPIC output actually goes from 0 diff to +5V diff so really only 17 bits at ADC Data Parallelization (serial to ||) –24 streams of serial 18 bit data are rearranged into 24 parallel 18 bit words via CPLD on BEB Voltage and Bias supply –Provide adjustable upper and lower rail voltages for clocks (three “types” – parallel, serial, reset) –Provide adjustable “high” rails for bias drives (OD, guard, RD) –Pass through negative substrate supply from external power supply Control and Monitoring –Provide raft heater power drive (resistors on raft baseplate) –Provide temp and voltage digitization* –Provide fast spy digitization (TBD)* * Not on present version.

13. LSST Electronics Review – BNL, January 25-26 201213 RCC Functionality - Backplane Connects 6 BEBs to one RCM Bus power to all BEBs Bus timing signals to appropriate BEBs –ASPIC timing to all BEBs –Parallel Clocks to half of BEBs –Serial (+Reset) Clocks to other BEB of each pair Handle slow control signals to BEBs –Provide Geographic address for each BEB –Bus SPI bus and SPI address to all BEBs

14. LSST Electronics Review – BNL, January 25-26 201214 RCC Functionality – Raft Control Module (RCM) Provide timing signals to backplane –Timing engine in FPGA based upon 50 MHz clock programmed by simple, concatenated commands – a dozen or so lines of code define an entire readout sequence –Convert single ended timing signals from FPGA to LVDS Receive digitized words from backplane and transmit packets to DAQ (|| to serial) –Twenty four 18 bit words per BEB per pixel position –Build data packets to pass to DAQ engine in FPGA that then ships data to SDS over a 3.2 Gbps link (significant spare bandwidth given 144 Mpixels x 2.25 Bytes in 2 sec) Control ADCs and DACs on BEBs through SPI –Measure temperatures –Measure voltages and currents –Set voltages and currents Configure FEB (ASPIC and CABAC) through SPI –Set gains, integrations times, voltages, test modes, monitoring paths –Single SPI bus, 7 address bits available, SS done in BEB CPLD

15. LSST Electronics Review – BNL, January 25-26 201215 RCC Functionality – Raft Control Module (RCM) - II USB Interface (present version only) –Debugging interface –Data interface for a small subset of data (limited by FPGA buffer memory) TCM Interface –Originally ideated as similar to NOvA scheme Reference clock input Control stream input / output Reconfigure FPGA via CPLD on RCM –Next version will use only reference clock and fast command signals from TCM Single serial input 8b/10b Command carried on clock line, single byte, 255 possible commands (e.g. synch, reset, begin readout, …. Reconfigure FPGA via standard JTAG No USB

16. LSST Electronics Review – BNL, January 25-26 201216 RCC – Back End Board (BEB); Backplane; Raft Control Module (RCM) BEB – 24 eighteen bit 1 MHz ADCs with high speed differential drivers DAC-Op amp driver combos to supply programmable voltages to FEB CPLD to decode and drive LVDS timing signals to FEB CPLD to deserialize, store, and transmit ADC serial streams to RCM RCM collates data from 6 BEBs and spits out a 3.125 Gbps stream to DAQ

17. LSST Electronics Review – BNL, January 25-26 201217 BEB Block (crudely) 24 X (Diff Amp + ADC) LVDS Drive X 14 Video In Timing Out SPI Bus to FEB V from DACs V from Regulators V from PDS FP Temp measure BEB SPI bus CPLD Backplane To RCM Clocks ADC cvt Power SPI + Addr Bus

18. LSST Electronics Review – BNL, January 25-26 201218 RCM (crudely) Backplane From RCM Clocks ADC Conv Power SPI Addr Bus FPGA DAQ Clock TCM Data

19. LSST Electronics Review – BNL, January 25-26 201219 Institutional Responsibilities – RTM Electronics (2011) IN2P3 –ASPIC Design Fabrication Testing –CABAC Design Fabrication Testing –CCD Readout Harvard –RCC – all boards Design Fabrication Testing Firmware –TCM –Vertical Slice Test Digital testing Preparation for CCD readout Penn –FEB Design Fabrication Testing –Vertical Slice Test Analog testing Preparation for CCD readout SLAC –DAQ Firmware in RCM FPGA Testing –Vertical Slice Test Preparation for CCD readout Ohio State –Optical Transition Module Design Fabrication Testing

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