SN54HC191_14 Datasheet, PDF (1/21 Pages) Texas Instruments – 4-BIT SYNCHRONOUS UP/DOWN BINARY COUNTERS

SN54HC191, SN74HC191
4ĆBIT SYNCHRONOUS UP/DOWN BINARY COUNTERS
D Wide Operating Voltage Range of 2 V to 6 V
D Outputs Can Drive Up To 10 LSTTL Loads
D Low Power Consumption, 80-µA Max I_CC
D Typical t_pd = 13 ns
D ±4-mA Output Drive at 5 V
D Low Input Current of 1 µA Max
D Single Down/Up Count-Control Line
D Look-Ahead Circuitry Enhances Speed of
Cascaded Counters
D Fully Synchronous in Count Modes
D Asynchronously Presettable With Load
Control
description/ordering information
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.
SCLS121D − DECEMBER 1982 − REVISED OCTOBER 2003
SN54HC191 . . . J OR W PACKAGE
SN74HC191 . . . D, N, OR NS PACKAGE
(TOP VIEW)
B1
Q_B 2
Q_A 3
CTEN 4
D/U 5
Q_C 6
Q_D ⁷
GND ⁸
16 V_CC
15 A
14 CLK
13 RCO
12 MAX/MIN
11 LOAD
10 _C
9_D
SN54HC191 . . . FK PACKAGE
(TOP VIEW)
Q_A
CTEN
NC
D/U
Q_C
3 2 1 20 19
4
18
5
17
6
16
7
15
8
14
9 10 11 12 13
CLK
RCO
NC
MAX/MIN
LOAD
NC − No internal connection
ORDERING INFORMATION
TA
PACKAGE†
ORDERABLE
PART NUMBER
TOP-SIDE
MARKING
PDIP − N
Tube of 25
SN74HC191N
SN74HC191N
Tube of 40
SN74HC191D
−40°C to 85°C SOIC − D
Reel of 2500
Reel of 250
SN74HC191DR
SN74HC191DT
HC191
SOP − NS
Reel of 2000 SN74HC191NSR
HC191
CDIP − J
Tube of 25
SNJ54HC191J
SNJ54HC191J
−55°C to 125°C CFP − W
Tube of 150
SNJ54HC191W
SNJ54HC191W
LCCC − FK
Tube of 55
SNJ54HC191FK
SNJ54HC191FK
† _{Package drawings, standard packing quantities, thermal data, symbolization, and PCB design guidelines are}
available at www.ti.com/sc/package.
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
• POST OFFICE BOX 655303 DALLAS, TEXAS 75265
Copyright  2003, Texas Instruments Incorporated
On products compliant to MILĆPRFĆ38535, all parameters are tested
unless otherwise noted. On all other products, production
processing does not necessarily include testing of all parameters.
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