TECHNICAL DATA
IN74AC161
Presettable Counter
High-Speed Silicon-Gate CMOS
The IN74AC161 is identical in pinout to the LS/ALS161,
HC/HCT161. The device inputs are compatible with standard CMOS
outputs; with pullup resistors, they are compatible with LS/ALS outputs.
The IN74AC161 is programmable 4-bit synchronous modulo-16
counter that feature parallel Load, asynchronous Reset, a Carry Output for
cascading and count-enable controls.
The IN74AC161 is binary counter with asynchronous Reset.
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Outputs Directly Interface to CMOS, NMOS, and TTL
Operating Voltage Range: 2.0 to 6.0 V
Low Input Current: 1.0 μA; 0.1 μA @ 25° C
High Noise Immunity Characteristic of CMOS Devices
Outputs Source/Sink 24 mA
ORDERING INFORMATION
IN74AC161N Plastic
IN74AC161D SOIC
TA = -40° to 85° C for all packages
LOGIC DIAGRAM
PIN ASSIGNMENT
Outputs
PIN 16 =VCC
PIN 8 = GND
FUNCTION TABLE
Inputs
Reset Load Enable Enable
Outputs
Q1 Q2
Clock
X
Q0
Q3
Function
P
X
X
X
L
T
X
X
L
L
H
H
H
H
H
X
L
L
L
L
L
Reset to “0”
Preset Data
No count
No count
Count
P0
P1
P2
P3
H
H
H
X
No change
No change
Count up
X
H
X
H
X
No change
No count
X=don’t care
P0,P1,P2,P3 = logic level of Data inputs
Ripple Carry Out = Enable T • Q0 • Q1 • Q2 • Q3
Rev. 00