# Presentation: 686928

## SNAPElectrical Design Estimates

- November 16, 2001
- C. Paul Earle

- Super Nova/Acceleration Probe

## SNAP Functional Block Diagram

**Scene**

**Door**
**open / close**

**Focus**
**Control**

**Readout**
**Control Logic**

**FPE**

**Instrument Control Electronics**

**Data Buffering**
** **

**Thermal Control  & Monitoring**

**FPA**

**Detectors**

**Shutter**

**Filters**

**CDS**

**A/D**

**DC-DC**
**Converter**

**1553 I/F**

**Science Data I/F**

**Mass Storage**
**(S/C)**

**ICE**

**S/C Power**

**S/C C&DH**

**Door**

**Spectrograph**

**Shutter**
**Control**

**Bright Object**
**Detector**

**A/D**

## Science Data Rate

- 200Sec
- integration

- 20Ssec
- readout

- 220Sec

_**FPA Size:**_
**144 CCDs @ 1.6Kx1.6K each ~ 368.6 Mpix**
**44 HgCdTe @ 2Kx2K each ~ 176 Mpix**
_**Spectrograph: **_**1Kx1K ~ 1Mpix**
_**Average Data Rate:**_
**==> 545 Mpix for each 200Sec exposure**
**==> Data rate (avg)  ~ (545Mpix/220Sec) ~ 2.5Mpix/s**
**       ****~  40 Mbps @16-bits/pix**
**       ****~  20 Mbps (with 2:1 loss-less compression)**

## Focal Plane Electronics

-    4 A/Ds
-    4 CDS chips (Correlated Double Sampling)
-    Bias & Power Generation
-    Sequencer & Clock Drivers
- _188 Readout ASICs_
- ~ 10 boards (12” x 12”)
-     18 ASICs each, 9 ASICs per side
-     2 boxes ~ (13.5”x13.5”x6”) each ~ 9lbs each
-     Total Power: 156Watt (peak), 22 Watt (avg.)

## Thermal Control

- - 70 zones, controlled within _+_0.5 deg. C of set point
- - 1 Heater and 1 Temperature Sensor per zone
- - Each CCD controlled within _+_0.1 deg. C of set point
- - Unregulated Heater Power (120Watts)

- Heater

- Sensor
- (AD590)

- i (T)

- V+

**(1 of 258)**

- Current
- TLM

- V+

- V+

- _Figure 2._

## CCD Temperatures

**Mux**
**16-ch**
- AD506

- .
- .
- .

**A/D **
**Conv.**
- AD 1672

- To Memory

- Power
- Temp
- ...

**H/K**
**FIFO**

- +

- -

- V-

- V-

- Housekeeping Data

- _Figure 3._

- CCD temps
- (188)

**Mux**
**16-ch**
- AD506

**A/D **
**Conv.**
- AD 1672

- To Memory

**H/K**
**FIFO**

- _Zone Temperatures & Other Telemetry points _

**(1 of 11)**

**(1 of 5)**

## Readout Data Buffering

**Buffer**

**To Storage**

- _Figure 4._

- Capture& Control Logic
- FPGA
**(1 of 1)**

**Processor Card I/F**

**Digital**
**MUX**
**(4:1)**

**CCD I/F**

**FPE I/F**

- 4

- 1

**(1 of 188)**

**(1 of 188)**

## Mechanism Control

- _Figure 6._

- (Door Control Electronics)

## Processor & Memory Board

- UTMC
- 69R000

- Startup ROM

- EEPROM Memory
- (Data Processing)

- Ethernet I/F

- 1553 I/F

- 1553 I/F

- xcvr

- xfmr

- xcvr

- xfmr

- xfmr

- xfmr

- RAM
- (Data Processing)

- S/W Dev.

- _Figure 5._

## Power Distribution

- Converters

- +28 VDC

- _Figure 7._

- -

- +

- Current Sense

- -

- +

- Voltage Sense

- _+_15 V

- _+_5 V

| End Items | Avg. Power |
| --- | --- |
| Main Power Board | 20 Watts |
| Thermal Control | 12 Watts |
| Main Processor | 4 Watts |
| Mechanism Control | 6 Watts |
| Housekeeping | 16 Watts |
| Data Buffering | 9 Watts |
| FPE Power Boards | 9.4Watts
(33Watts peak) |
| FPE Boxes | 22Watts
(156 Watts peak) |
| Main Box Total: | 76.4 Watts |
| Mechanisms | 4 Watts |
| Thermal S/S | 100 Watts |
| Instrument Total: | 202 Watts |

## Board Estimates

**Thermal Control (4W)**

**Thermal Control (4W)**

**Thermal Control (4W)**

- 9  in

- 10 in

**Data Buffer (3W)**

**Data Buffer (3W)**

**Data Buffer (3W)**

**Processor (4W)**

**Mech Control (6W)**

**Housekeeping (16W)**

**Main Power (20W)**

**FPE Power (9.4W)**

## Main Electronics Box Summary

- 11 in

- 19 in

- 10 in

**Estimated Mass ~ 44 lbs**
**Estimated Power ~ 76 Watts (avg.) Estimated Size ~ (19 x 11 x 10) in.**