This part is a kind of semiconductor called 74LS90.

Function of this product has Decade and Binary Counters.

Manufacturers : Fairchild Semiconductor

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Some of the text within the PDF file :

DM74LS90 Decade and Binary Counters August 1986 Revised March 2000 DM74LS90 Decade and Binary Counters General Description Each of these monolithic counters contains four masterslave flip-flops and additional gating to provide a divide-bytwo counter and a three-stage binary counter for which the count cycle length is divide-by-five for the DM74LS90. All of these counters have a gated zero reset and the DM74LS90 also has gated set-to-nine inputs for use in BCD nine’s complement applications. To use their maximum count length (decade or four bit binary), the B input is connected to the QA output. The input count pulses are applied to input A and the outputs are as described in the appropriate truth table. A symmetrical divide-by-ten count can be obtained from the DM74LS90 counters by con [ ... ]

74LS90 PDF Datasheet Download