DM74LS191N Datasheet PDF – 4-Bit Binary Counter

Part Number: DM74LS191N

Function: Synchronous 4-Bit Binary Counter

Package: DIP 16 Pin Type

Manufacturer: Fairchild Semiconductor


DM74LS191N Binary Counter



The DM74LS191N circuit is a synchronous, reversible, up/down counter. Synchronous operation is provided by having all flip-flops clocked simultaneously, so that the outputs change simultaneously when so instructed by the steering logic. This mode of operation eliminates the output count ing spikes normally associated with asynchronous (ripple clock) counters.

The outputs of the four master-slave flip-flops are triggered on a low-to-high level transition of the clock input, if the enable input is low. A high at the enable input inhibits counting. Level changes at either the enable input or the down/ up input should be made only when the clock input is high. The direction of the count is determined by the level of the down/up input. When low, the counter counts up and when high, it counts down.

Block Diagram :



1. Counts 8-4-2-1 BCD or binary
2. Single down/up count control line
3. Count enable control input
4. Ripple clock output for cascading
5. Asynchronously presettable with load control
6. Parallel outputs
7. Cascadable for n-bit applications
8. Average propagation delay 20 ns
9. Typical clock frequency 25 MHz
10. Typical power dissipation 100 mW


DM74LS191N Datasheet PDF Download

DM74LS191N pdf

Other data sheets are available within the file: 74LS191, 74LS191M, 74LS191N, DM74LS191, DM74LS191M