Solitron Devices

Overview

Solitron Devices, Inc. is an American semiconductor manufacturer.

Products

UA3533

In 1971, Unisem advertised model UA3533, a single-chip keyboard encoder with 4608 bits of look-up table ROM capacity. The next year, it was advertised as a Solitron Devices product, following the 1971 acquisition of United Aircraft’s Unisem semiconductor division by Solitron Devices.

The product was specified as follows:

• Static keyboard encoder
• 128 coded key capability
• 4 modes
• 512 unique 9 bit codes
• Keybounce effects eliminated by internal strobe control
• Two key rollover
• Single switch closure addressing
• Shift lock with indicator capability
• Ignores false pulses up to 4 µs

As a static encoder, this will not be matrix scan. Consequently, this may be a two-of-N encoder, requiring switches with dual isolated outputs. There seems to be no other documented mention of this chip, although it does appear on surplus part sites.

Documentation

All material was scanned by Bitsavers unless otherwise noted.

• Unisem Corp. UA3533 advertisement, Electromechanical Design, Vol. 15 No. 6, June 1971 (painfully extracted from the Internet Archive)
• Solitron Devices ROMs advertisement, The Electronic Engineer, Vol. 31 No. 1, January 1972