5-1
FACT DATA
  
  
The MC74AC257/74ACT257 is a quad 2-input multiplexer with 3-state outputs.
Four bits of data from two sources can be selected using a Common Data Select
input. The four outputs present the selected data in true (noninverted) form. The
outputs may be switched to a high impedance state by placing a logic HIGH on
the common Output Enable (OE) input, allowing the outputs to interface directly
with bus-oriented systems.
•Multiplexer Expansion by Tying Outputs Together
•Noninverting 3-State Outputs
•Outputs Source/Sink 24 mA
• ′ACT257 Has TTL Compatible Inputs
1516 14 13 12 11 10
21 3 4 5 6 7
VCC 9
8
OE I0c I1c ZcI0d I1d Zd
S I0a I1a ZaI0b I1b ZbGND
PIN NAMES
S Common Data Select Input
OE 3-State Output Enable Input
I0a–I0d Data Inputs from Source 0
I1a–I1d Data Inputs from Source 1
Za–Zd3-State Multiplexer Outputs
TRUTH TABLE
Output
Enable Select
Input Data
Inputs Outputs
OE S I0I1Z
H X X X Z
L H X L L
L H X H H
L L L X L
L L H X H
H = HIGH Voltage Level
L = LOW Voltage Level
X = Immaterial
Z = High Impedance


QUAD 2-INPUT
MULTIPLEXER WITH
3-STATE OUTPUTS
N SUFFIX
CASE 648-08
PLASTIC
D SUFFIX
CASE 751B-05
PLASTIC
LOGIC SYMBOL
S
OE I0a I1a I0b I1b
Zb
I0c I1c I0d I1d
ZaZcZd
MC74AC257 MC74ACT257
5-2
FACT DATA
FUNCTIONAL DESCRIPTION
The MC74AC257/74ACT257 is a quad 2-input multiplexer
with 3-state outputs. It selects four bits of data from two
sources under control of a Common Data Select input. When
the Select input is LOW , the I0x inputs are selected and when
Select is HIGH, the I1x inputs are selected. The data on the
selected inputs appears at the outputs in true (noninverted)
form. The device is the logic implementation of a 4-pole,
2-position switch where the position of the switch is
determined by the logic levels supplied to the Select input. The
logic equations for the outputs are shown below:
Za = OE•(I1a•S+I0a•S)
Zb = OE•(I1b•S+I0b•S)
Zc = OE•(I1c•S+I0c•S)
Zd = OE•(I1d•S+I0d•S)
When the Output Enable input (OE) is HIGH, the outputs
are forced to a high impedance state. If the outputs are tied
together, all but one device must be in the high impedance
state to avoid high currents that would exceed the maximum
ratings. Designers should ensure the Output Enable signals to
3-state devices whose outputs are tied together are designed
so there is no overlap.
Please note that this diagram is provided only for the understanding of logic
operations and should not be used to estimate propagation delays.
OE I0a I1a I0b I1b I0c I1c I0d I1d S
ZaZbZcZd
LOGIC DIAGRAM
MC74AC257 MC74ACT257
5-3
FACT DATA
MAXIMUM RATINGS*
Symbol Parameter Value Unit
VCC DC Supply Voltage (Referenced to GND) –0.5 to +7.0 V
Vin DC Input Voltage (Referenced to GND) –0.5 to VCC +0.5 V
Vout DC Output Voltage (Referenced to GND) –0.5 to VCC +0.5 V
Iin DC Input Current, per Pin ±20 mA
Iout DC Output Sink/Source Current, per Pin ±50 mA
ICC DC VCC or GND Current per Output Pin ±50 mA
Tstg Storage Temperature –65 to +150 °C
* Maximum Ratings are those values beyond which damage to the device may occur. Functional operation should be restricted to the Recommended
Operating Conditions.
RECOMMENDED OPERATING CONDITIONS
Symbol Parameter Min Typ Max Unit
VCC
Supply Voltage
′AC 2.0 5.0 6.0
V
VCC
Supply Voltage
′ACT 4.5 5.0 5.5
V
Vin, Vout DC Input Voltage, Output Voltage (Ref. to GND) 0 VCC V
tr, tf
Input Rise and Fall Time (Note 1)
′AC Devices except Schmitt Inputs
VCC @ 3.0 V 150
tr, tf
Input Rise and Fall Time (Note 1)
′AC Devices except Schmitt Inputs
VCC @ 4.5 V 40 ns/V
r, tf
′AC Devices except Schmitt Inputs
VCC @ 5.5 V 25
tr, tf
Input Rise and Fall Time (Note 2)
′ACT Devices except Schmitt Inputs
VCC @ 4.5 V 10
ns/V
tr, tf
Input Rise and Fall Time (Note 2)
′ACT Devices except Schmitt Inputs
VCC @ 5.5 V 8.0
ns/V
TJJunction Temperature (PDIP) 140 °C
TAOperating Ambient Temperature Range –40 25 85 °C
IOH Output Current — High –24 mA
IOL Output Current — Low 24 mA
1. Vin from 30% to 70% VCC; see individual Data Sheets for devices that differ from the typical input rise and fall times.
2. Vin from 0.8 V to 2.0 V ; see individual Data Sheets for devices that dif fer from the typical input rise and fall times.
MC74AC257 MC74ACT257
5-4
FACT DATA
DC CHARACTERISTICS
Symbol
Parameter
VCC
(V)
74AC 74AC
Unit
Conditions
Symbol
Parameter
VCC
(V)
TA = +25°CTA =
–40°C to +85°C
Unit
Conditions
Typ Guaranteed Limits
VIH
Minimum High Level
Input Voltage
3.0 1.5 2.1 2.1 VOUT = 0.1 V
Input Voltage
4.5 2.25 3.15 3.15 V or VCC – 0.1 V
5.5 2.75 3.85 3.85
VIL
Maximum Low Level
Input Voltage
3.0 1.5 0.9 0.9 VOUT = 0.1 V
Input Voltage
4.5 2.25 1.35 1.35 V or VCC – 0.1 V
5.5 2.75 1.65 1.65
VOH
Minimum High Level
Output Voltage
3.0 2.99 2.9 2.9 IOUT = –50 µA
Output Voltage
4.5 4.49 4.4 4.4 V
5.5 5.49 5.4 5.4
V
*VIN = VIL or VIH
3.0 2.56 2.46
V
–12 mA
4.5 3.86 3.76
V
IOH –24 mA
5.5 4.86 4.76 –24 mA
VOL
Maximum Low Level
Output Voltage
3.0 0.002 0.1 0.1 IOUT = 50 µA
Output Voltage
4.5 0.001 0.1 0.1 V
5.5 0.001 0.1 0.1
V
*VIN = VIL or VIH
3.0 0.36 0.44
V
12 mA
4.5 0.36 0.44
V
IOL 24 mA
5.5 0.36 0.44 24 mA
IIN
Maximum Input
Leakage Current
5.5
±0.1
µA
VI = VCC, GND
Leakage Current
5.5
±0.1
µA
VI = VCC, GND
IOZ
Maximum
3-State
Current
VI (OE) = VIL, VIH
3-State
Current
5.5 ±0.5 ±5.0 µA VI = VCC, GND
Current
VO = VCC, GND
IOLD
†Minimum Dynamic
Output Current
5.5 75 mA VOLD = 1.65 V Max
IOHD
Output Current
5.5 –75 mA VOHD = 3.85 V Min
ICC
Maximum Quiescent
Supply Current
5.5
8.0
µA
VIN = VCC or GND
Supply Current
5.5
8.0
µA
VIN = VCC or GND
* All outputs loaded; thresholds on input associated with output under test.
†Maximum test duration 2.0 ms, one output loaded at a time.
Note: IIN and ICC @ 3.0 V are guaranteed to be less than or equal to the respective limit @ 5.5 V VCC.
MC74AC257 MC74ACT257
5-5
FACT DATA
AC CHARACTERISTICS (For Figures and Waveforms — See Section 3)
Symbol
Parameter
VCC*
(V)
74AC 74AC
Unit
Fig.
No.
Symbol
Parameter
VCC*
(V)
TA = +25°C
CL = 50 pF
TA = –40°C
to +85°C
CL = 50 pF
Unit
Fig.
No.
Min Typ Max Min Max
tPLH
Propagation Delay 3.3 1.5 5.0 8.5 1.0 9.0
ns
3-5
tPLH
In to Zn5.0 1.5 4.0 6.0 1.0 7.0
ns
3-5
tPHL
Propagation Delay 3.3 1.5 6.0 8.5 1.0 9.0
ns
3-5
tPHL
In to Zn5.0 1.5 4.5 6.0 1.0 7.0
ns
3-5
tPLH
Propagation Delay 3.3 1.5 7.0 10.5 1.5 11.5
ns
3-6
tPLH
S to Zn5.0 1.5 5.0 7.5 1.0 8.5
ns
3-6
tPHL
Propagation Delay 3.3 1.5 7.5 10.5 1.5 11.5
ns
3-6
tPHL
S to Zn5.0 1.5 5.5 7.5 1.0 8.5
ns
3-6
tPZH
Output Enable Time
3.3 1.5 6.5 9.5 1.0 10.5
ns
3-7
tPZH
Output Enable Time
5.0 1.5 5.0 7.5 1.0 8.5
ns
3-7
tPZL
Output Enable Time
3.3 1.5 5.5 9.0 1.0 10.0
ns
3-8
tPZL
Output Enable Time
5.0 1.5 5.0 8.5 1.0 9.5
ns
3-8
tPHZ
Output Disable Time
3.3 1.5 5.5 10.0 1.0 11.0
ns
3-7
tPHZ
Output Disable Time
5.0 1.5 5.0 9.0 1.0 10.0
ns
3-7
tPLZ
Output Disable Time
3.3 1.5 5.5 9.0 1.0 10.0
ns
3-8
tPLZ
Output Disable Time
5.0 1.5 5.0 8.0 1.0 9.0
ns
3-8
* Voltage Range 3.3 V is 3.3 V ±0.3 V.
Voltage Range 5.0 V is 5.0 V ±0.5 V.
MC74AC257 MC74ACT257
5-6
FACT DATA
DC CHARACTERISTICS
Symbol
Parameter
VCC
(V)
74ACT 74ACT
Unit
Conditions
Symbol
Parameter
VCC
(V)
TA = +25°CTA =
–40°C to +85°C
Unit
Conditions
Typ Guaranteed Limits
VIH
Minimum High Level
Input Voltage
4.5 1.5 2.0 2.0
V
VOUT = 0.1 V
Input Voltage
5.5 1.5 2.0 2.0
V
or VCC – 0.1 V
VIL
Maximum Low Level
Input Voltage
4.5 1.5 0.8 0.8
V
VOUT = 0.1 V
Input Voltage
5.5 1.5 0.8 0.8
V
or VCC – 0.1 V
VOH
Minimum High Level
Output Voltage
4.5 4.49 4.4 4.4
V
IOUT = –50 µA
Output Voltage
5.5 5.49 5.4 5.4
V
*VIN = VIL or VIH
4.5 3.86 3.76 V
IOH
–24 mA
5.5 4.86 4.76
IOH
–24 mA
VOL
Maximum Low Level
Output Voltage
4.5 0.001 0.1 0.1
V
IOUT = 50 µA
Output Voltage
5.5 0.001 0.1 0.1
V
*VIN = VIL or VIH
4.5 0.36 0.44 V
IOL
24 mA
5.5 0.36 0.44
IOL
24 mA
IIN
Maximum Input
Leakage Current
5.5
±0.1
µA
VI = VCC, GND
Leakage Current
5.5
±0.1
µA
VI = VCC, GND
∆ICCT Additional Max. ICC/Input 5.5 0.6 1.5 mA VI = VCC – 2.1 V
IOZ
Maximum
3-State
Current
VI (OE) = VIL, VIH
3-State
Current
5.5 ±0.5 ±5.0 µA VI = VCC, GND
Current
VO = VCC, GND
IOLD
†Minimum Dynamic
Output Current
5.5 75 mA VOLD = 1.65 V Max
IOHD
Output Current
5.5 –75 mA VOHD = 3.85 V Min
ICC
Maximum Quiescent
Supply Current
5.5
8.0
µA
VIN = VCC or GND
Supply Current
5.5
8.0
µA
VIN = VCC or GND
* All outputs loaded; thresholds on input associated with output under test.
†Maximum test duration 2.0 ms, one output loaded at a time.
MC74AC257 MC74ACT257
5-7
FACT DATA
AC CHARACTERISTICS (For Figures and Waveforms — See Section 3)
Symbol
Parameter
VCC*
(V)
74ACT 74ACT
Unit
Fig.
No.
Symbol
Parameter
VCC*
(V)
TA = +25°C
CL = 50 pF
TA = –40°C
to +85°C
CL = 50 pF
Unit
Fig.
No.
Min Typ Max Min Max
tPLH
Propagation Delay
In to Zn
5.0
1.5
5.0
7.0
1.0
7.5
ns
3-6
tPLH
In to Zn
5.0
1.5
5.0
7.0
1.0
7.5
ns
3-6
tPHL
Propagation Delay
In to Zn
5.0
2.0
6.0
7.5
1.5
8.5
ns
3-6
tPHL
In to Zn
5.0
2.0
6.0
7.5
1.5
8.5
ns
3-6
tPLH
Propagation Delay
S to Zn
5.0
2.0
7.0
9.5
1.5
10.5
ns
3-6
tPLH
S to Zn
5.0
2.0
7.0
9.5
1.5
10.5
ns
3-6
tPHL
Propagation Delay
S to Zn
5.0
2.5
7.0
10.5
2.0
11.5
ns
3-6
tPHL
S to Zn
5.0
2.5
7.0
10.5
2.0
11.5
ns
3-6
tPZH Output Enable Time 5.0 2.0 6.0 8.0 1.5 9.0 ns 3-7
tPZL Output Enable Time 5.0 2.0 6.0 8.0 1.5 9.0 ns 3-8
tPHZ Output Disable Time 5.0 2.5 6.5 9.0 1.5 10.0 ns 3-7
tPLZ Output Disable Time 5.0 2.0 6.0 7.5 1.5 8.5 ns 3-8
* Voltage Range 5.0 V is 5.0 V ±0.5 V.
CAPACITANCE
Symbol Parameter Value
Typ Unit Test Conditions
CIN Input Capacitance 4.5 pF VCC = 5.0 V
CPD Power Dissipation Capacitance 50 pF VCC = 5.0 V
MC74AC257 MC74ACT257
5-8
FACT DATA
OUTLINE DIMENSIONS
N SUFFIX
PLASTIC DIP PACKAGE
CASE 648–08
ISSUE R
D SUFFIX
PLASTIC SOIC PACKAGE
CASE 751B–05
ISSUE J
NOTES:
1. DIMENSIONING AND TOLERANCING PER
ANSI Y14.5M, 1982.
2. CONTROLLING DIMENSION: MILLIMETER.
3. DIMENSIONS A AND B DO NOT INCLUDE
MOLD PROTRUSION.
4. MAXIMUM MOLD PROTRUSION 0.15 (0.006)
PER SIDE.
5. DIMENSION D DOES NOT INCLUDE DAMBAR
PROTRUSION. ALLOWABLE DAMBAR
PROTRUSION SHALL BE 0.127 (0.005) TOTAL
IN EXCESS OF THE D DIMENSION AT
MAXIMUM MATERIAL CONDITION.
1 8
16 9
SEATING
PLANE
F
J
M
RX 45
_
G
8 PLP
–B–
–A–
M
0.25 (0.010) B S
–T–
D
K
C
16 PL
S
B
M
0.25 (0.010) A S
T
DIM MIN MAX MIN MAX
INCHESMILLIMETERS
A9.80 10.00 0.386 0.393
B3.80 4.00 0.150 0.157
C1.35 1.75 0.054 0.068
D0.35 0.49 0.014 0.019
F0.40 1.25 0.016 0.049
G1.27 BSC 0.050 BSC
J0.19 0.25 0.008 0.009
K0.10 0.25 0.004 0.009
M0 7 0 7
P5.80 6.20 0.229 0.244
R0.25 0.50 0.010 0.019
____
NOTES:
1. DIMENSIONING AND TOLERANCING PER ANSI
Y14.5M, 1982.
2. CONTROLLING DIMENSION: INCH.
3. DIMENSION L TO CENTER OF LEADS WHEN
FORMED PARALLEL.
4. DIMENSION B DOES NOT INCLUDE MOLD FLASH.
5. ROUNDED CORNERS OPTIONAL.
–A–
B
FC
S
HGD
J
L
M
16 PL
SEATING
1 8
916
K
PLANE
–T–
M
A
M
0.25 (0.010) T
DIM MIN MAX MIN MAX
MILLIMETERSINCHES
A0.740 0.770 18.80 19.55
B0.250 0.270 6.35 6.85
C0.145 0.175 3.69 4.44
D0.015 0.021 0.39 0.53
F0.040 0.70 1.02 1.77
G0.100 BSC 2.54 BSC
H0.050 BSC 1.27 BSC
J0.008 0.015 0.21 0.38
K0.110 0.130 2.80 3.30
L0.295 0.305 7.50 7.74
M0 10 0 10
S0.020 0.040 0.51 1.01
____
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MC74AC257/D
*MC74AC257/D*
◊