This post explains for the TTL DM7493.
The Part Number is 7493.
The function of this semiconductor is Decade and Binary Counter.
Manufacturer: National Semiconductor, Fairchild Semiconductor
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The 7493 is Decade and Binary Counter.
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 90A and divideby-eight for the 93A.
All of these counters have a gated zero reset and the 90A 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 90A counters by connecting the QD output to the A input and applying the input count to the B input which gives a divide-by-ten square wave at output QA.
1. Typical power dissipation 45 mW
2. Count frequency 42 MHz