Ex workshop spare parts, these have been sitting in the Power Supply drawers (embedded in ESD foam to protect the legs) for yonks ...
SILICON GENERAL - PWM device 
Type: SG3823N
Batch codes: 7946 & 7950
Function: High performance PW Modulator for use with high frequency current mode power supplies 
Datasheet is readily available online
14 pin DIL Plastic 
            NEW Old Stock