I am looking for a data sheet (or at least a pinout) for an IC numbered
PIC900C. Despite the number, this is not a microcontroller, it's some
kind of power driver IC -- from the 'house code' on it, I suspect it's
little more than a transistor array, here [1] configured as a full-H driver
foo a motor. FWIW it's in a 'wide' 18 pin DIL package with a metal top
surface to attach to a heatsink.
I beleive it was made by Unitrode in the early 1980s. Alas the only
Unitrode data book I could find on the web was too early for it.
[1] On the 'servo' (notor control) board of an HP9144 tape drive.
-tony