Specification	SN74HC191DR

Count Rate	24 MHz
Direction	Up, Down
Logic Type	Binary Counter
Mounting Type	Surface Mount
Number of Bits per Element	4
Number of Elements	1
Operating Temperature [Max]	85 °C
Operating Temperature [Min]	-40 °C
Package / Case	16-SOIC
Package / Case [x]	0.154 in
Package / Case [y]	3.9 mm
Reset	Asynchronous
Supplier Device Package	16-SOIC
Timing	Synchronous
Trigger Type	Positive Edge
Voltage - Supply [Max]	6 V
Voltage - Supply [Min]	2 V

SN74HC191 Series

High Speed CMOS Logic Presettable Synchronous 4-Bit Binary Up/Down Counters

Part	Logic Type	Operating Temperature [Max]	Operating Temperature [Min]	Count Rate	Package / Case	Package / Case	Package / Case	Number of Elements	Timing	Direction	Reset	Supplier Device Package	Number of Bits per Element	Mounting Type	Trigger Type	Voltage - Supply [Min]	Voltage - Supply [Max]	Package / Case [x]	Package / Case [y]
Texas Instruments SN74HC191NSR	Binary Counter	85 °C	-40 °C	24 MHz	0.209 "	16-SOIC	5.3 mm	1	Synchronous	Down Up	Asynchronous	16-SO	4	Surface Mount	Positive Edge	2 V	6 V
Texas Instruments CD74HC191E	Binary Counter	125 °C	-55 °C	35 MHz	0.3 in	16-DIP	7.62 mm	1	Synchronous	Down Up	Asynchronous	16-PDIP	4	Through Hole	Positive Edge	2 V	6 V
Texas Instruments SN74HC191NG4	Binary Counter	85 °C	-40 °C	24 MHz	0.3 in	16-DIP	7.62 mm	1	Synchronous	Down Up	Asynchronous	16-PDIP	4	Through Hole	Positive Edge	2 V	6 V
Texas Instruments CD74HC191M	Binary Counter	125 °C	-55 °C	35 MHz		16-SOIC		1	Synchronous	Down Up	Asynchronous	16-SOIC	4	Surface Mount	Positive Edge	2 V	6 V	0.154 in	3.9 mm
Texas Instruments CD74HC191MT	Binary Counter	125 °C	-55 °C	35 MHz		16-SOIC		1	Synchronous	Down Up	Asynchronous	16-SOIC	4	Surface Mount	Positive Edge	2 V	6 V	0.154 in	3.9 mm
Texas Instruments SN74HC191DR	Binary Counter	85 °C	-40 °C	24 MHz		16-SOIC		1	Synchronous	Down Up	Asynchronous	16-SOIC	4	Surface Mount	Positive Edge	2 V	6 V	0.154 in	3.9 mm
Texas Instruments SN74HC191D	Binary Counter	85 °C	-40 °C	24 MHz		16-SOIC		1	Synchronous	Down Up	Asynchronous	16-SOIC	4	Surface Mount	Positive Edge	2 V	6 V	0.154 in	3.9 mm
Texas Instruments CD74HC191EG4	Binary Counter	125 °C	-55 °C	35 MHz	0.3 in	16-DIP	7.62 mm	1	Synchronous	Down Up	Asynchronous	16-PDIP	4	Through Hole	Positive Edge	2 V	6 V
Texas Instruments CD74HC191M96	Binary Counter	125 °C	-55 °C	35 MHz		16-SOIC		1	Synchronous	Down Up	Asynchronous	16-SOIC	4	Surface Mount	Positive Edge	2 V	6 V	0.154 in	3.9 mm
Texas Instruments SN74HC191DRG4	Binary Counter	85 °C	-40 °C	24 MHz		16-SOIC		1	Synchronous	Down Up	Asynchronous	16-SOIC	4	Surface Mount	Positive Edge	2 V	6 V	0.154 in	3.9 mm

Pricing

Prices provided here are for design reference only. For realtime values and availability, please visit the distributors directly

Distributor	Package	Quantity	$

Digikey	Cut Tape (CT)	1	$ 0.65
		10	$ 0.57
		25	$ 0.54
		100	$ 0.44
		250	$ 0.41
		500	$ 0.35
		1000	$ 0.28
	Digi-Reel®	1	$ 0.65
		10	$ 0.57
		25	$ 0.54
		100	$ 0.44
		250	$ 0.41
		500	$ 0.35
		1000	$ 0.28
	Tape & Reel (TR)	2500	$ 0.23
		5000	$ 0.21
		12500	$ 0.20
		25000	$ 0.19
Texas Instruments	LARGE T&R	1	$ 0.36
		100	$ 0.28
		250	$ 0.20
		1000	$ 0.15

Description

General part information

SN74HC191 Series

The ’HC191 devices are 4-bit synchronous, reversible, up/down binary counters. Synchronous counting operation is provided by having all flip-flops clocked simultaneously so that the outputs change coincident with each other when instructed by the steering logic. This mode of operation eliminates the output counting spikes normally associated with asynchronous (ripple-clock) counters.

The outputs of the four flip-flops are triggered on a low- to high-level transition of the clock (CLK) input if the count-enable (CTEN)\ input is low. A high at CTEN\ inhibits counting. The direction of the count is determined by the level of the down/up (D/U\) input. When D/U\ is low, the counter counts up, and when D/U\ is high, it counts down.

These counters feature a fully independent clock circuit. Change at the control (CTEN\ and D/U\) inputs that modifies the operating mode have no effect on the contents of the counter until clocking occurs. The function of the counter is dictated solely by the condition meeting the stable setup and hold times.

Documents

Technical documentation and resources

SN54HC191, SN74HC191 datasheet (Rev. D)

Data sheet