
HD74HC257
Quad. 2-to-1-line Data Selectors/Multiplexers
(with noninverted 3-state outputs)
Description
The large output drive capability coupled with the 3-state feature make this device ideal for interfacing with
bus lines in a bus organized system. When the output control input line is taken high, the outputs of all four
multiplexers are sent into a high impedance state. When the output control line is low, the select input
chooses whether the A or B input is used.
Features
• High Speed Operation: tpd (Data to Y) = 10.5 ns typ (CL = 50 pF)
• High Output Current: Fanout of 15 LSTTL Loads
• Wide Operating Voltage: VCC = 2 to 6 V
• Low Input Current: 1 µA max
• Low Quiescent Supply Current: ICC (static) = 4 µA max (Ta = 25°C)
Function Table
Inputs Outputs
Output Control Select A B Y
LL L X L
LL H X H
LHXLL
LH X H H
H X X X High impedance
Notes H: high level, L: low level, X: irrelevant

HD74HC257
Pin Arrangement
Select
1A
1B
1Y
2A
2B
2Y
GND
1
S
2
3
4
5
6
7
1A
1B
1Y
2A
2B
2Y
3Y
OC
4A
4B
4Y
3A
3B
8
16
15
14
13
12
11
10
9
V
CC
Output
control
4A
4B
4Y
3A
3B
3Y
(Top view)
Absolute Maximum Ratings
Item Symbol Rating Unit
Supply voltage range V
Input voltage V
Output voltage V
DC current drain per pin I
DC current drain per VCC, GND ICC, I
DC input diode current I
DC output diode current I
Power dissipation per package P
CC
IN
OUT
OUT
GND
IK
OK
T
Storage temperature Tstg –65 to +150 °C
–0.5 to +7.0 V
–0.5 to VCC + 0.5 V
–0.5 to VCC + 0.5 V
±35 mA
±75 mA
±20 mA
±20 mA
500 mW
2

HD74HC257
DC Characteristics
Ta = –40 to
Ta = 25°C
Item Symbol V
Input voltage V
IH
(V) Min Typ Max Min Max Unit Test Conditions
CC
2.0 1.5 — — 1.5 — V
4.5 3.15 — — 3.15 —
6.0 4.2 — — 4.2 —
V
IL
2.0 — — 0.5 — 0.5 V
4.5 — — 1.35 — 1.35
6.0 — — 1.8 — 1.8
Output voltage V
OH
2.0 1.9 2.0 — 1.9 — V Vin = VIH or VILIOH = –20 µA
4.5 4.4 4.5 — 4.4 —
6.0 5.9 6.0 — 5.9 —
4.5 4.18 — — 4.13 — IOH = –6 mA
6.0 5.68 — — 5.63 — IOH = –7.8 mA
V
OL
2.0 — 0.0 0.1 — 0.1 V Vin = VIH or VILIOL = 20 µA
4.5 — 0.0 0.1 — 0.1
6.0 — 0.0 0.1 — 0.1
4.5 — — 0.26 — 0.33 IOL = 6 mA
6.0 — — 0.26 — 0.33 IOL = 7.8 mA
Off-state output
I
OZ
6.0 — — ±0.5 — ±5.0 µA Vin = VIH or VIL,
current
Input current Iin 6.0 — — ±0.1 — ±1.0 µA Vin = VCC or GND
Quiescent supply
I
CC
6.0 — — 4.0 — 40 µA Vin = VCC or GND, Iout = 0 µA
current
+85°C
Vout = V
or GND
CC
4

AC Characteristics (CL = 50 pF, Input tr = tf = 6 ns)
Ta = –40 to
Ta = 25°C
Item Symbol V
Propagation delay t
PHL
(V) Min Typ Max Min Max Unit Test Conditions
CC
2.0 — — 115 — 145 ns Data to Y
time 4.5 — 11 23 — 29
6.0 — — 20 — 25
t
PLH
2.0 — — 115 — 145 ns
4.5 — 10 23 — 29
6.0 — — 20 — 25
t
PHL
2.0 — — 115 — 145 ns Select to Y
4.5 — 14 23 — 29
6.0 — — 20 — 25
t
PLH
2.0 — — 115 — 145 ns
4.5 — 14 23 — 29
6.0 — — 20 — 25
Output enable t
ZL
2.0 — — 150 — 190 ns Output control to Y
time 4.5 — 11 30 — 38
6.0 — — 26 — 33
t
ZH
2.0 — — 150 — 190 ns
4.5 — 13 30 — 38
6.0 — — 26 — 33
Output disable t
LZ
2.0 — — 150 — 190 ns Output control to Y
time 4.5 — 14 30 — 38
6.0 — — 26 — 33
t
HZ
2.0 — — 150 — 190 ns
4.5 — 18 30 — 38
6.0 — — 26 — 33
Output rise/fall t
time t
TLH
THL
2.0 — — 60 — 75 ns
4.5 — 4 12 — 15
6.0 — — 10 — 13
Input capacitance Cin — — 5 10 — 10 pF
+85°C
HD74HC257
5

19.20
20.00 Max
16 9
1.3
Unit: mm
6.30
7.40 Max
81
1.11 Max
2.54 ± 0.25
0.48 ± 0.10
5.06 Max
2.54 Min
0.51 Min
Hitachi Code
JEDEC
EIAJ
Weight
7.62
+ 0.13
0.25
– 0.05
0° – 15°
(reference value)
DP-16
Conforms
Conforms
1.07 g

16
Unit: mm
10.06
10.5 Max
9
5.5
1
0.80 Max
1.27
*0.42 ± 0.08
0.40 ± 0.06
*Dimension including the plating thickness
Base material dimension
8
0.12
0.10 ± 0.10
0.15
M
2.20 Max
7.80
0.20 ± 0.04
*0.22 ± 0.05
0.70 ± 0.20
Hitachi Code
JEDEC
EIAJ
(reference value)
Weight
+ 0.20
– 0.30
1.15
0° – 8°
FP-16DA
—
Conforms
0.24 g

16
Unit: mm
9.9
10.3 Max
9
1
1.27
0.635 Max
*0.42 ± 0.08
0.40 ± 0.06
*Dimension including the plating thickness
Base material dimension
8
0.25
+ 0.11
– 0.04
0.14
0.15
3.95
1.75 Max
M
6.10
1.08
0.20 ± 0.03
*0.22 ± 0.03
0.60
Hitachi Code
JEDEC
EIAJ
Weight
+ 0.10
– 0.30
0° – 8°
+ 0.67
– 0.20
(reference value)
FP-16DN
Conforms
Conforms
0.15 g

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received the latest product standards or specifications before final design, purchase or use.
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contact Hitachi’s sales office before using the product in an application that demands especially high
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traffic, safety equipment or medical equipment for life support.
4. Design your application so that the product is used within the ranges guaranteed by Hitachi particularly
for maximum rating, operating supply voltage range, heat radiation characteristics, installation
conditions and other characteristics. Hitachi bears no responsibility for failure or damage when used
beyond the guaranteed ranges. Even within the guaranteed ranges, consider normally foreseeable
failure rates or failure modes in semiconductor devices and employ systemic measures such as failsafes, so that the equipment incorporating Hitachi product does not cause bodily injury, fire or other
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