DAC Board: PCB Electrical Tests

This document outlines basic electrical tests to verify the AMDC DAC expansion board, an accessory for the AMDC Rev D. The expansion board must not be plugged into the AMDC while performing any electrical tests! Use an external power supply to verify the correct operation of board before connecting it to the AMDC.

Electrical Shorts

  1. Verify all pins on U12 have no shorts between adjacent pins

Applying Power

All power signals on the DAC board are isolated from the supplied power from the AMDC. To differentiate, this document will prefix all supply signals with SUPPLY_

The DAC expansion board signals, +/- 12V, +5V, and 0V, are generated from DC-to-DC converters U10 and U7. The DC-to-DC converters are each supplied with SUPPLY_5V and SUPPLY_GND to generate these signals. Apply the following voltages using an external power supply:

  1. SUPPLY_5V must be applied to pin 1 on U7 and pin 2 on U10.

  2. SUPPLY_GND must be applied to pin 2 on U7 and pin 1 on U10.

Pin 1 can be identified on both U7 and U10 by a square pad.

Basic Voltage Tests

  1. Verify pin 1 on U12 is at 2.5V with respect to GND (C40 is connected to 2.5V and GND)

  2. Verify pin 7 on U12 is at 5V with respect to GND (C36 and C37 connect 5V to GND)

  3. Verify pin 3 on U8 is at +12V with respect to GND (C28 is connected to +12V and GND)

  4. Verify pin 3 on U6 is at -12V with respect to GND (C31 is connected to -12V and GND)

  5. Verify on power up all channel outputs are at 0V with respect to GND