74AC161
SYNCHRONOUS PRESETTABLE 4-BIT COUNTER
s
s
s
s
s
s
s
s
s
HIGH SPEED:
f
MAX
= 125MHz (TYP.) at V
CC
= 5V
LOW POWER DISSIPATION:
I
CC
= 8µA(MAX.) at T
A
=25°C
HIGH NOISE IMMUNITY:
V
NIH
= V
NIL
= 28 % V
CC
(MIN.)
50Ω TRANSMISSION LINE DRIVING
CAPABILITY
SYMMETRICAL OUTPUT IMPEDANCE:
|I
OH
| = I
OL
= 24mA (MIN)
BALANCED PROPAGATION DELAYS:
t
PLH
≅
t
PHL
OPERATING VOLTAGE RANGE:
V
CC
(OPR) = 2V to 6V
PIN AND FUNCTION COMPATIBLE WITH
74 SERIES 161
IMPROVED LATCH-UP IMMUNITY
DIP
SOP
TSSOP
ORDER CODES
PACKAGE
DIP
SOP
TSSOP
TUBE
74AC161B
74AC161M
DESCRIPTION
The 74AC161 is an advanced high-speed CMOS
SYNCRONOUS PRESETTABLE COUNTER
fabricated with sub-micron silicon gate and
double-layer metal wiring C
2
MOS tecnology. It is a
4 bit binary counter with Asynchronous Clear.
The circuit have four fundamental modes of
operation, in order of preference: synchronous
reset, parallel load, count-up and hold. Four
control inputs, (CLEAR), (LOAD), (PE) and (TE),
determine the mode of operation as shown in the
Truth Table. A LOW signal on CLEAR overrides
PIN CONNECTION AND IEC LOGIC SYMBOLS
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counting and parallel loading and sets all outputs
on LOW state. A LOW signal on LOAD overrides
counting and allows information on Parallel Data
inputs to be loaded into the flip-flop on the next
rising edge of CLOCK. With LOAD and CLEAR
HIGH, PE and TE permit counting when both are
HIGH. Conversely, a LOW signal on either PE and
TE inhibits counting.
The CARRY OUTPUT is HIGH when TE is HIGH
and counter is in state 15.
All inputs and outputs are equipped with
protection circuits against static discharge, giving
them 2KV ESD immunity and transient excess
voltage.
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T&R
74AC161MTR
74AC161TTR
July 2001
1/13
74AC161
ABSOLUTE MAXIMUM RATINGS
Symbol
V
CC
V
I
V
O
I
IK
I
OK
I
O
Supply Voltage
DC Input Voltage
DC Output Voltage
DC Input Diode Current
DC Output Diode Current
DC Output Current
Parameter
Value
-0.5 to +7
-0.5 to V
CC
+ 0.5
-0.5 to V
CC
+ 0.5
±
20
±
20
±
50
±
300
-65 to +150
300
Unit
V
V
V
mA
mA
mA
mA
°C
°C
I
CC
or I
GND
DC V
CC
or Ground Current
T
stg
Storage Temperature
T
L
Lead Temperature (10 sec)
Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these conditions is
not implied.
RECOMMENDED OPERATING CONDITIONS
Symbol
V
CC
V
I
V
O
T
op
dt/dv
Supply Voltage
Input Voltage
Output Voltage
Operating Temperature
Input Rise and Fall Time V
CC
= 3.0, 4.5 or 5.5V (note 1)
Parameter
Value
2 to 6
1) V
IN
from 30% to 70% of V
CC
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t(
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b
-O
P
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8
0 to V
CC
0 to V
CC
s)
t(
uc
Unit
V
V
V
-55 to 125
°C
ns/V
4/13
单片机
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