CY74FCT191T
4-BIT UP/DOWN BINARY COUNTER
SCCS016A 鈥?MAY 1994 鈥?REVISED SEPTEMBER 2001
D
D
D
D
D
D
D
Function, Pinout, and Drive Compatible
With FCT and F Logic
Reduced V
OH
(Typically = 3.3 V) Versions
of Equivalent FCT Functions
Edge-Rate Control Circuitry for
Significantly Improved Noise
Characteristics
I
off
Supports Partial-Power-Down Mode
Operation
ESD Protection Exceeds JESD 22
鈥?2000-V Human-Body Model (A114-A)
鈥?200-V Machine Model (A115-A)
鈥?1000-V Charged-Device Model (C101)
Matched Rise and Fall Times
64-mA Output Sink Current
32-mA Output Source Current
Q OR SO PACKAGE
(TOP VIEW)
P
1
Q
1
Q
0
CE
U/D
Q
2
Q
3
GND
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
V
CC
P
0
CP
RC
TC
PL
P
2
P
3
description
The CY74FCT191T is a reversible modulo-16 binary counter, featuring synchronous counting and
asynchronous presetting. The preset allows the CY74FCT191T to be used in programmable dividers. The count
enable input, terminal count output, and ripple-clock output make possible a variety of methods of implementing
multiusage counters. In the counting modes, state changes are initiated by the rising edge of the clock.
This device is fully specified for partial-power-down applications using I
off
. The I
off
circuitry disables the outputs,
preventing damaging current backflow through the device when it is powered down.
PIN DESCRIPTION
NAME
CE
CP
P
PL
U/D
Q
RC
TC
DESCRIPTION
Count enable input (active low)
Clock pulse input (active rising edge)
Parallel data inputs
Asynchronous parallel load input (active low)
Up/down count control input
Flip-flop outputs
Ripple clock output (active low)
Terminal count output
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.
Copyright
錚?/div>
2001, 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.
POST OFFICE BOX 655303
鈥?/div>
DALLAS, TEXAS 75265
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