Philips 74HCT191
The 74HC/HCT191 are high-speed Si-gate CMOS devices and are pin compatible with low power Schottky TTL (LSTTL). They are specified in compliance with JEDEC standard no. The 74HC/HCT191 are asynchronously presettable 4-bit binary up/down counters.| Part No. | 74HCT191 |
|---|---|
| Datasheet | 74HCT191 Download |
| Manufacturer |  Philips |
| Description | Presettable synchronous 4-bit binary up/down counter |
| Buy | Stock & Price |
FEATURES
● Synchronous reversible counting● Asynchronous parallel load
● Count enable control for synchronous expansion
● Single up/down control input
● Output capability: standard
● ICC category: MSI
GENERAL DESCRIPTION
7A. They contain four master/slave flip-flops with internal gating and steering logic to provide asynchronous preset and synchronous count-up and count-down operation. Asynchronous parallel load capability permits the counter to be preset to any desired number. Information present on the parallel data inputs (D0 to D3) is loaded into the counter and appears on the outputs when the parallel load (PL) input is LOW. As indicated in the function table, this operation overrides the counting function. Counting is inhibited by a HIGH level on the count enable (CE) input. When CE is LOW internal state changes are initiated synchronously by the LOW-to-HIGH transition of the clock input. The up/down (U/D) input signal determines the direction of counting as indicated in the function table.
