PC-21

The PC21 Test Board from Centralab Semiconductor is specifically designed for testing the A111 and A111F detectors. This printed circuit board includes dedicated component locations for detectors and utilizes a ground plane construction to effectively minimize external signal pick-up.

Key electrical inputs include a detector input (IN) that should be AC coupled with a high voltage capacitor, a test input (TEST IN) for circuit testing, and a supply voltage (Vs) ranging from +4 to +10 VDC. Outputs include a positive TTL type output (OUT), a positive analog output (A OUT), and a positive output through a buffer/line drive IC (BUF OUT).

The board features several components, including filter capacitors (C1, C2, C3) with values of 1 uF, 4.7 uF, and 0.1 uF, a 2 pF test capacitor (CT), and a 50 ohm test pulse termination (RO). It also accommodates user-supplied components such as a detector bias resistor (R) and a detector coupling capacitor (C).

Testing can be performed using a pulser with a small 2 pF test capacitor to inject a test charge. The unit triggers on the negative-going edge of the test pulse, which requires a transition time of less than 20 ns. The dimensions of the PC21 board are 1.75 inches square (4.45 cm square).