ꢀꢁꢂ ꢃ ꢄꢅ ꢆ ꢇꢆ ꢈ ꢀꢁꢉ ꢃꢄ ꢅꢆ ꢇꢆ
ꢃ ꢊꢋꢌ ꢍ ꢀꢎ ꢁꢅꢄꢏꢐ ꢁꢐ ꢑꢀ ꢋꢌ ꢁꢒꢏꢎ ꢅꢐ ꢑ ꢁꢍ ꢓꢏ ꢀ
SCLS297D − JANUARY 1996 − REVISED SEPTEMBER 2003
D
D
D
D
D
Wide Operating Voltage Range of 2 V to 6 V
Outputs Can Drive Up To 10 LSTTL Loads
D
D
D
D
D
Low Input Current of 1 µA Max
Internal Look-Ahead for Fast Counting
Carry Output for n-Bit Cascading
Synchronous Counting
Low Power Consumption, 80-µA Max I
CC
Typical t = 14 ns
pd
4-mA Output Drive at 5 V
Synchronously Programmable
SN54HC161 . . . J OR W PACKAGE
SN74HC161 . . . D, N, NS, OR PW PACKAGE
(TOP VIEW)
SN54HC161 . . . FK PACKAGE
(TOP VIEW)
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
CLR
CLK
A
V
CC
RCO
3
2
1
20 19
18
A
B
Q
Q
4
5
6
7
8
A
B
Q
Q
Q
Q
A
B
C
D
17
16
15
14
B
C
D
NC
C
NC
Q
Q
C
D
D
ENP
GND
ENT
LOAD
9 10 11 12 13
NC − No internal connection
description/ordering information
These synchronous, presettable counters feature an internal carry look-ahead for application in high-speed
counting designs. The ’HC161 devices are 4-bit binary counters. Synchronous operation is provided by having
all flip-flops clocked simultaneously so that the outputs change coincident with each other when so instructed
by the count-enable (ENP, ENT) inputs and internal gating. This mode of operation eliminates the output
counting spikes that are normally associated with synchronous (ripple-clock) counters. A buffered clock (CLK)
input triggers the four flip-flops on the rising (positive-going) edge of the clock waveform.
ORDERING INFORMATION
ORDERABLE
PART NUMBER
TOP-SIDE
MARKING
†
PACKAGE
T
A
PDIP − N
Tube of 25
Tube of 40
Reel of 2500
Reel of 250
Reel of 2000
Tube of 90
Reel of 2000
Reel of 250
Tube of 25
Tube of 150
Tube of 55
SN74HC161N
SN74HC161N
SN74HC161D
SN74HC161DR
SN74HC161DT
SN74HC161NSR
SN74HC161PW
SN74HC161PWR
SN74HC161PWT
SNJ54HC161J
SNJ54HC161W
SNJ54HC161FK
SOIC − D
SOP − NS
HC161
HC161
−40°C to 85°C
TSSOP − PW
HC161
CDIP − J
CFP − W
LCCC − FK
SNJ54HC161J
SNJ54HC161W
SNJ54HC161FK
−55°C to 125°C
†
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.
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Copyright 2003, Texas Instruments Incorporated
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