74HC191

The 74HC191 is designed as high-speed si-gate CMOS devices and are pin compatible with low power schottky TTL (LSTTL). It is specified in compliance with JEDEC standard no. 7A. It is asynchronously presettable 4-bit binary up/down counters and it contains four master/slave flip-flops with internal gating and steering logic to provide asynchronous preset and synchronous count-up and count-down operation.

The six features of the 74HC191. The first one is synchronous reversible counting. The second one is asynchronous parallel load. The third one is count enable control for synchronous expansion. The fourth one is single up/down control input. The fifth one is its output capability would be standard. The sixth one is its ICC category would be MSI. That are all the main features.

Some important AC characteristics and specifications of the 74HC191 have been concluded into several points as follow.For Tamb=25°C the first one is about its propagation delay CP to Qn which would be typ 72ns and max 220ns at Vcc=2.0V and would be typ 26ns and max 44ns at Vcc=4.5V and would be typ 21ns and max 37ns at Vcc=6.0V. The second one is about its propagation delay CP to TC which would be typ 83ns and max 255ns at Vcc=2.0V and typ 30ns and max 51ns at Vcc=4.5V and would be typ 24ns and max 43ns at Vcc=6.0V. The third one is about its output transition time which would be typ 19ns and max 75ns at Vcc=2.0V and typ 7ns and max 15ns at Vcc=4.5V and would be typ 6ns and max 13ns at Vcc=6.0V.

Also for the Tamb range of -40 to +125°C the first one is about its propagation delay An to Yn which would be max 330ns at Vcc=2.0V and would be max 66ns at Vcc=4.5V and would be max 56ns at Vcc=6.0V. The second one is about its propagation delay E3 to Yn which would be max 395ns at Vcc=2.0V and max 77ns at Vcc=4.5V and would be max 65ns at Vcc=6.0V. The third one is about its output transition time which would be max 110ns at Vcc=2.0V and max 22ns at Vcc=4.5V and would be max 19ns at Vcc=6.0V. And so on. For more information about the 74HC191 please contact us.