LBNL LLRF Expansion Board
(actual size 5.0 x 3.1 inches = 127 x 79 mm)
- 3 Photodiode Bias ports: +5V out, current monitor to 10 mA full scale (and trip)
- 3 Thermistor ports
- 2 Optical atten control ports: few mA, few V
- 2 VCXO control ports: few mA, few V
- control and readout via digital I/O on existing LLRF4 board
Translated to something more real:
- 3 x 10mA 5V regulator with enable: 3 x LP2989
- 3 x high-side current sense: 3 x MAX4172
- 3 x over-current comparator: 3 x TLV7211
- 3 x 14-bit 200 kSample/s ADC: TLC3548I (bias current monitor)
- set/trip/reset remote/local digital logic: XC9536XL
- 3 x 24-bit 60 Sample/s ADC: AD7794 (50 kOhm thermistor bridge)
- 4 x 14-bit 500 kSample/s DAC: AD5644 (VCXO and Optical atten, unbuffered 0 to 2.5V)
- SPI-like expansion ports for LLRF4 FPGA (code not written, except for AD5644)
- power input nominally +12V, but LP2989 will work with +6V to +16V
The schematic is done in xcircuit,
and the board layout is done in PCB.
Both are Free Software.
They may or may not be available or useful on Microsoft-based computers.
This board design was done on
Debian 5.0 (Lenny),
a stable Linux distribution.
Specifically, this was Lenny's stock xcircuit (3.6.135), and pcb was
updated to pcb-20080601 to get the photo-realistic board preview feature.
Packets for Download
Larry Doolittle, LBNL
April 27, 2009