74ACT257
QUAD 2 CHANNEL MULTIPLEXER (3-STATE)
s
s
s
s
s
s
s
s
s
HIGH SPEED: t
PD
= 5 ns (TYP.) at V
CC
= 5V
LOW POWER DISSIPATION:
I
CC
= 4
µA(MAX.)
at T
A
=25°C
COMPATIBLE WITH TTL OUTPUTS
V
IH
= 2V (MIN.), V
IL
= 0.8V (MAX.)
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) = 4.5V to 5.5V
PIN AND FUNCTION COMPATIBLE WITH
74 SERIES 257
IMPROVED LATCH-UP IMMUNITY
DIP
SOP
TSSOP
ORDER CODES
PACKAGE
DIP
SOP
TSSOP
TUBE
74ACT257B
74ACT257M
DESCRIPTION
The 74ACT257 is an advanced high-speed CMOS
QUAD 2-CHANNEL MULTIPLEXER (3-STATE)
fabricated with sub-micron silicon gate and
double-layer metal wiring C
2
MOS tecnology.
It is composed of an independent 2-channel
multiplexer with common SELECT and ENABLE
(OE)inputs. It is a non-inverting multiplexer. When
the ENABLE input is held HIGH, the outputs are
forced to a high impedance state. When the
PIN CONNECTION AND IEC LOGIC SYMBOLS
O
so
b
te
le
r
P
uc
od
s)
t(
bs
-O
SELECT input is held LOW, "A" data is selected;
when SELECT input is held HIGH, "B" data is
selected.
The device is designed to interface directly High
Speed CMOS systems with TTL, NMOS and
CMOS output voltage levels.
All inputs and outputs are equipped with
protection circuits against static discharge, giving
them 2KV ESD immunity and transient excess
voltage.
et
l
o
P
e
od
r
s)
t(
uc
T&R
74ACT257MTR
74ACT257TTR
April 2001
1/11
74ACT257
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
±
200
-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
Storage Temperature
T
stg
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
= 4.5 to 5.5V (note 1)
Parameter
Value
4.5 to 5.5
0 to V
CC
0 to V
CC
8
1) V
IN
from 0.8V to 2.0V
O
so
b
te
le
r
P
uc
od
s)
t(
so
b
-O
te
le
r
P
-55 to 125
od
s)
t(
uc
Unit
V
V
V
°C
ns/V
3/11
74ACT257
DC SPECIFICATIONS
Test Condition
Symbol
Parameter
V
CC
(V)
4.5
5.5
4.5
5.5
4.5
5.5
4.5
5.5
V
OL
Low Level Output
Voltage
4.5
5.5
4.5
5.5
I
I
I
OZ
Input Leakage Cur-
rent
High Impedance
Output Leakege
Current
Max I
CC
/Input
Quiescent Supply
Current
Dynamic Output
Current (note 1, 2)
5.5
5.5
5.5
5.5
5.5
V
O
= 0.1 V or
V
CC
-0.1V
V
O
= 0.1 V or
V
CC
-0.1V
I
O
=-50
µA
I
O
=-50
µA
I
O
=-24 mA
I
O
=-24 mA
I
O
=50
µA
I
O
=50
µA
I
O
=24 mA
I
O
=24 mA
V
I
= V
CC
or GND
V
I
= V
IH
or V
IL
V
O
= V
CC
or GND
V
I
= V
CC
- 2.1V
V
I
= V
CC
or GND
V
OLD
= 1.65 V max
V
OHD
= 3.85 V min
0.6
4.4
5.4
3.86
4.86
0.001
0.001
0.1
0.1
0.36
0.36
± 0.1
± 0.5
T
A
= 25°C
Min.
2.0
2.0
Typ.
1.5
1.5
1.5
1.5
4.49
5.49
0.8
0.8
4.4
5.4
3.76
4.76
0.1
0.1
0.44
0.44
Max.
Value
-40 to 85°C
Min.
2.0
2.0
0.8
0.8
4.4
5.4
3.7
4.7
0.1
0.1
V
Max.
-55 to 125°C
Min.
2.0
2.0
0.8
0.8
V
Max.
V
Unit
V
IH
V
IL
V
OH
High Level Input
Voltage
Low Level Input
Voltage
High Level Output
Voltage
I
CCT
I
CC
I
OLD
I
OHD
1) Maximum test duration 2ms, one output loaded at time
2) Incident wave switching is guaranteed on trasmission lines with impedances as low as 50Ω
AC ELECTRICAL CHARACTERISTICS
(C
L
= 50 pF, R
L
= 500
Ω,
Input t
r
= t
f
= 3ns)
Symbol
Parameter
b
O
t
PLH
t
PHL
Propagation Delay
Time A, B to Y
t
PLH
t
PHL
Propagation Delay
Time SELECT to Y
t
PZL
t
PZH
Output Enable
Time
t
PLZ
t
PHZ
Output Disable
Time
so
te
le
r
P
uc
od
V
CC
(V)
5.0
(*)
5.0
(*)
5.0
(*)
5.0
(*)
Test Condition
T
A
= 25°C
Min.
Typ.
5.0
6.0
5.0
6.0
Max.
8.0
9.0
8.0
9.0
s)
t(
bs
-O
et
l
o
4
P
e
od
r
±5
1.5
40
75
-75
±1
s)
t(
uc
0.5
0.5
±1
±5
1.6
80
50
-50
µA
mA
mA
µA
mA
mA
Value
-40 to 85°C
Min.
Max.
9.0
10.0
9.0
10.0
-55 to 125°C
Min.
Max.
9.0
10.0
9.0
10.0
ns
ns
ns
ns
Unit
(*) Voltage range is 5.0V ± 0.5V
4/11
74ACT257
CAPACITIVE CHARACTERISTICS
Test Condition
Symbol
Parameter
V
CC
(V)
5.0
5.0
5.0
f
IN
= 10MHz
T
A
= 25°C
Min.
Typ.
5
8
25
Max.
Value
-40 to 85°C
Min.
Max.
-55 to 125°C
Min.
Max.
pF
pF
pF
Unit
C
IN
C
OUT
C
PD
Input Capacitance
Output
Capacitance
Power Dissipation
Capacitance (note
1)
1) C
PD
is defined as the value of the IC’s internal equivalent capacitance which is calculated from the operating current consumption without
load. (Refer to Test Circuit). Average operating current can be obtained by the following equation. I
CC(opr)
= C
PD
x V
CC
x f
IN
+ I
CC
/n (per
circuit)
TEST CIRCUIT
TEST
t
PLH
, t
PHL
t
PZL
, t
PLZ
t
PZH
, t
PHZ
C
L
= 50pF or equivalent (includes jig and probe capacitance)
R
L
= R
1
= 500Ω or equivalent
R
T
= Z
OUT
of pulse generator (typically 50Ω)
O
so
b
te
le
r
P
uc
od
s)
t(
bs
-O
et
l
o
P
e
od
r
s)
t(
uc
SWITCH
Open
2V
CC
Open
5/11
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