Nexperia

74HC191

Presettable synchronous 4-bit binary up/down counter

aaa-024389

VOH

VOL

VM

VI

VI

GND

GND

tTLH

tTHL

VM

VM

tW

trec

tPHL

10 %

10 %

90 %

90 %

Qn output

PL input

CP input

Measurement points are given in Table 9.

Logic levels VOL and VOH are typical output voltage levels that occur with the output load.

Fig. 15. The parallel load input (PL) to clock (CP) recovery times, parallel load pulse width and output (Qn)

transition times

aaa-024391

GND

GND

Vl

VM

CP input

GND

VM

VM

CE, U/D input

CE, U/D input

Vl

Vl

tsu

th

th

tsu

Measurement points are given in Table 9.

The shaded areas indicate when the input is permitted to change for predictable output performance.

Fig. 16. The count enable and up/down count inputs (CE, U/D) to clock input (CP) set-up and hold times

74HC191

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Product data sheet

Rev. 6 — 8 September 2021

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