74ACT11191 Datasheet, PDF (1/9 Pages) Texas Instruments – SYNCHRONOUS 4-BIT UP/DOWN BINARY COUNTER

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74ACT11191
SYNCHRONOUS 4ĆBIT UP/DOWN BINARY COUNTER
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SCAS106A − D3455, FEBRUARY 1990 − REVISED APRIL 1993
• Inputs Are TTL-Voltage Compatible
• Single Down/Up Count Control Line
• Look-Ahead Circuitry Enhances Speed of
Cascaded Counters
• Fully Synchronous in Count Modes
• Asynchronously Presettable With Load
Control
• Flow-Through Architecture Optimizes
PCB Layout
• Center-Pin V_CC and GND Configurations to
Minimize High-Speed Switching Noise
• EPICt (Enhanced-Performance Implanted
CMOS) 1-mm Process
• Package Options Include Plastic
Small-Outline Packages and Standard
Plastic 300-mil DIPs
DW OR N PACKAGE
(TOP VIEW)
RCO 1
Q_A 2
Q_B 3
GND 4
GND 5
GND 6
GND 7
Q_C 8
Q_D 9
MAX/MIN 10
20 D/U
19 CLK
18 A
17 B
16 V_CC
15 V_CC
14 C
13 D
12 CTEN
11 LOAD
description
The 74ACT11191 is a synchronous, 4-bit binary reversible up/down counter. A synchronous counting operation
is provided by having all flip-flops clocked simultaneously so that the outputs change coincident with each other
when so 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 input if the enable
input (CTEN) 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. Changes at the control inputs (CTEN and D/U) that
will modify the operating mode have no effect on the contents of the counter until clocking occurs. The function
of the counter will be dictated solely by the condition meeting the stable setup and hold times.
logic symbol^†
CTEN ¹²
20
D/U
19
CLK
LOAD ¹¹
A ¹⁸
B ¹⁷
14
C
D ¹³
CTRDIV16
G1
M2 [DOWN] _2(CT=0)Z6
M3 [UP]
3(CT=15)Z6
1,2−/1,3+
G4
6,1,4
C5
5D
[1]
[2]
[4]
[8]
10
MAX/MIN
1
RCO
2
QA
3
QB
8
QC
9 _QD
† _{This symbol is in accordance with ANSI/IEEE Std 91-1984}
and IEC Publication 617-12.
EPIC is a trademark of Texas Instruments Incorporated.
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.
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Copyright  1993, Texas Instruments Incorporated
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