Texas Instruments SN76489

The SN76489 was originally designed to be used in the TI-99/4 computer, where it was first called the TMS9919 and later SN94624, and had a 500 kHz max clock input rate.

Or typically 108 Hz to 111.6 kHz, with an NTSC colorburst (~3.58 MHz) clock input – a range from roughly A2 (two octaves below middle A) to 5–6 times the generally accepted limits of human audio perception.

These modified sound chips were incorporated into the systems' video display processor (VDP).

Although basic functionality is almost identical to that of the original SN76489A, a few small differences exist: Another clone is the NCR 8496, used in some models of the Tandy 1000 computer.

Later Tandy 1000 machines (notably the SL, TL and RL series) integrated the SN76496's functionality into the PSSJ ASIC.