The counter operates by input signals, and processes from the current number to the next number by the output of the observation signal. The counter has an “auto-reset” feature that returns it from 9 to 0.
Part number : 7490
Functions : Decade and Binary Counter
Package : 14 Pin Type
Manufacturer : Fairchild Semiconductor, National Semiconductor
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Description
7490 is a Tansistor-Transistor Logic (TTL) derived 4-bit binary synchronous counter (IC). This counter is used to count numbers from 0 to 9 and is output in binary format.
The DM7490A monolithic counter contains four master slave flip-flops and additional gating to provide a divide-by two counter and a three-stage binary counter for which the count cycle length is divide-by-five. The counter has a gated zero reset and also has gated set to-nine inputs for use in BCD nine’s complement applications.
Pinout :
To use the 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 counters by connecting the QDoutput to the A input and applying the input count to the B input which gives a divide-by-ten square wave at output QA.
7490 Logic Diagram
IC 7490 Datasheet PDF
Other data sheets within the file : DM7490A, DM7490AN