XD74LS90 Binary Coded Decimal Decade Counter IC

Description

A decade counter IC that advances it’s count on the descending edge of each clock pulse and outputs it’s count as a 4 bit binary coded decimal. This is the ideal decade counter for making clocks because just about any display is compatible with the 4 digit binary coded decimal output from this chip. To use a 7 segment LED display with this chip you’ll need need a 74LS48 or 74LS49 BCD to 7 segment decoder. HERE is a great tutorial on using this chip.

If you’re trying to build your own clock from one of Bolt Industries open source schematics, this  is the only BCD decade counter IC that will work. There’s something about the propagation speed of the same chip made by other brands that is too fast or too slow for the hours ones digit. Made by Xinluda. 14 pin DIP breadboard friendly package.

Datasheet:

XD74LS90

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