11 September 2023

SN75188 / MC1488

I have some MC1488/SN75188 ICs laying around. They are "line drivers designed to interface data terminal equipment with data communications equipment" (souce: TI datasheet); the first edition of the datasheet was in 1983. Today in 2023 they are practically useless from my current view of upcoming projects.

I checked the datasheet in search for ideas for some side-use-case application, like an oscillator, LED blinker, whatever, just to have an excuse to melt some solder.

While they contain 5 inverting logic gates, this xx88 chip requires dual power supply which is uncommon today. But scrolling down the datasheet, almost at the end, an "application information" turns a useless part into a possible lifesaver:

logic level converter sample application for SN75188 IC
Logic level translator applications. Courtesy of TI datasheet.


With a TTL or DTL input, these chips can be used to drive old digital technology like RTL, DTL, HNK or (negative) MOS. What for? Well, 1970's technology I like to play with is often built around non-modern TTL digital logic signals and in case of a chip failure these xx88 might help to obtain a properly formatted drive.