Part Number : DM74LS191N
Function :Synchronous 4-Bit Binary Counters
Manufacturer : Fairchild Semiconductor
Pinout : 
Description
The DM74LS191 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.
Datasheet PDF Download
Other datasheets in the file : 74LS191, 74LS191M, 74LS191N, DM74LS191, DM74LS191M