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Электронный компонент: IN74ACT257N

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IN74ACT257
1
Q
UAD
2-I
NPUT
D
ATA
S
ELECTOR
/M
ULTIPLEXER
WITH
3-S
TATE
O
UTPUTS
High-Speed Silicon-Gate CMOS
The IN74ACT257 is identical in pinout to the LS/ALS257,
HC/HCT257. The IN74ACT257 may be used as a level converter for
interfacing TTL or NMOS outputs to High Speed CMOS inputs.
This device selects a (4-bit) nibble from either the A or B inputs as
determined by the Select input. The nibble is presented at the outputs
in noninverted from when the Output Enable pin is at a low level. A high
level on the Output Enable pin switches the outputs into the high-
impedance state.
ћ TTL/NMOS Compatible Input Levels
ћ Outputs Directly Interface to CMOS, NMOS, and TTL
ћ Operating Voltage Range: 4.5 to 5.5 V
ћ Low Input Current: 1.0 A; 0.1 A @ 25њC
ћ Outputs Source/Sink 24 mA
ORDERING INFORMATION
IN74ACT257N Plastic
IN74ACT257D SOIC
T
A
= -40
њ to 85њ C for all
packages
FUNCTION TABLE
Inputs Outputs
Output
Enable
Select Y0-Y3
H X
Z
L L
A0-A3
L H
B0-B3
X=don't care
Z = high-impedance state
A0-A3,B0-B3=the levels of the
respective Nibble Inputs
LOGIC DIAGRAM
PIN 16 =V
CC
PIN 8 = GND
PIN ASSIGNMENT
IN74ACT257
2
MAXIMUM RATINGS
*
Symbol Parameter
Value
Unit
V
CC
DC Supply Voltage (Referenced to GND)
-0.5 to +7.0
V
V
IN
DC Input Voltage (Referenced to GND)
-0.5 to V
CC
+0.5
V
V
OUT
DC Output Voltage (Referenced to GND)
-0.5 to V
CC
+0.5
V
I
IN
DC Input Current, per Pin
20
mA
I
OUT
DC Output Sink/Source Current, per Pin
50
mA
I
CC
DC Supply Current, V
CC
and GND Pins
50
mA
P
D
Power Dissipation in Still Air, Plastic DIP+
SOIC Package+
750
500
mW
Tstg
Storage Temperature
-65 to +150
њC
T
L
Lead Temperature, 1 mm from Case for 10
Seconds
(Plastic DIP or SOIC Package)
260
њC
*
Maximum Ratings are those values beyond which damage to the device may occur.
Functional operation should be restricted to the Recommended Operating Conditions.
+Derating - Plastic DIP: - 10 mW/
њC from 65њ to 125њC
SOIC Package: : - 7 mW/
њC from 65њ to 125њC

RECOMMENDED OPERATING CONDITIONS
Symbol Parameter Min
Max
Unit
V
CC
DC Supply Voltage (Referenced to GND)
4.5
5.5
V
V
IN
, V
OUT
DC Input Voltage, Output Voltage (Referenced to GND)
0
V
CC
V
T
J
Junction Temperature (PDIP)
140
њC
T
A
Operating Temperature, All Package Types
-40
+85
њC
I
OH
Output Current - High
-24
mA
I
OL
Output Current - Low
24
mA
t
r
, t
f
Input Rise and Fall Time
*
(except Schmitt Inputs)
V
CC
=4.5 V
V
CC
=5.5 V
0
0
10
8.0
ns/V
*
V
IN
from 0.8 V to 2.0 V
This device contains protection circuitry to guard against damage due to high static voltages or
electric fields. However, precautions must be taken to avoid applications of any voltage higher than
maximum rated voltages to this high-impedance circuit. For proper operation, V
IN
and V
OUT
should be
constrained to the range GND