1/14
November 2004
s
HIGH SPEED: t
PD
= 3.7ns (TYP.) at V
CC
= 5V
s
LOW POWER DISSIPATION:
I
CC
= 4
A (MAX.) at T
A
=25C
s
HIGH NOISE IMMUNITY:
V
NIH
= V
NIL
= 28% V
CC
(MIN.)
s
POWER DOWN PROTECTION ON INPUTS
s
SYMMETRICAL OUTPUT IMPEDANCE:
|I
OH
| = I
OL
= 8mA (MIN)
s
BALANCED PROPAGATION DELAYS:
t
PLH
t
PHL
s
OPERATING VOLTAGE RANGE:
V
CC
(OPR) = 2V to 5.5V
s
PIN AND FUNCTION COMPATIBLE WITH
74 SERIES 257
s
IMPROVED LATCH-UP IMMUNITY
s
LOW NOISE: V
OLP
= 0.8V (MAX.)
DESCRIPTION
The 74VHC257 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 technology.
It is composed of four independent 2-channel
multiplexers with common SELECT and ENABLE
(OE) INPUT. The VHC257 is a non-inverting
multiplexer. When the ENABLE INPUT is held
"High", all outputs become in high impedance
state. If SELECT INPUT is held "Low", "A" data is
selected, when SELECT INPUT is "High", "B" data
is chosen.
Power down protection is provided on all inputs
and 0 to 7V can be accepted on inputs with no
regard to the supply voltage. This device can be
used to interface 5V to 3V.
All inputs and outputs are equipped with
protection circuits against static discharge, giving
them 2KV ESD immunity and transient excess
voltage.
74VHC257
QUAD 2 CHANNEL MULTIPLEXER (3-STATE)
Figure 1: Pin Connection And IEC Logic Symbols
Table 1: Order Codes
PACKAGE
T & R
SOP
74VHC257MTR
TSSOP
74VHC257TTR
TSSOP
SOP
Rev. 4
74VHC257
2/14
Figure 2: Input Equivalent Circuit
Table 2: Pin Description
Table 3: Truth Table
X : Don't Care
Z : High Impedance
Figure 3: Logic Diagram
This logic diagram has not be used to estimate propagation delays
PIN N
SYMBOL
NAME AND FUNCTION
1
SELECT
Common Data Select
Inputs
2, 5, 11, 14
1A to 4A
Data Inputs From Source
A
3, 6, 10, 13
1B to 4B
Data Inputs From Source
B
4, 7, 9, 12
1Y to 4Y
3 State Multiplexer
Outputs
15
OE
3 State Output Enable
Inputs (Active LOW)
8
GND
Ground (0V)
16
V
CC
Positive Supply Voltage
INPUTS
OUTPUT
OE
SELECT
A
B
Y
H
X
X
X
Z
L
L
L
X
L
L
L
H
X
H
L
H
X
L
L
L
H
X
H
H
74VHC257
3/14
Table 4: Absolute Maximum Ratings
Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these conditions is
not implied
Table 5: Recommended Operating Conditions
1) V
IN
from 30% to 70% of V
CC
Symbol
Parameter
Value
Unit
V
CC
Supply Voltage
-0.5 to +7.0
V
V
I
DC Input Voltage
-0.5 to +7.0
V
V
O
DC Output Voltage
-0.5 to V
CC
+ 0.5
V
I
IK
DC Input Diode Current
- 20
mA
I
OK
DC Output Diode Current
20
mA
I
O
DC Output Current
25
mA
I
CC
or I
GND
DC V
CC
or Ground Current
50
mA
T
stg
Storage Temperature
-65 to +150
C
T
L
Lead Temperature (10 sec)
300
C
Symbol
Parameter
Value
Unit
V
CC
Supply Voltage
2 to 5.5
V
V
I
Input Voltage
0 to 5.5
V
V
O
Output Voltage
0 to V
CC
V
T
op
Operating Temperature
-55 to 125
C
dt/dv
Input Rise and Fall Time (note 1) (V
CC
= 3.3
0.3V)
(V
CC
= 5.0
0.5V)
0 to 100
0 to 20
ns/V
74VHC257
4/14
Table 6: DC Specifications
Symbol
Parameter
Test Condition
Value
Unit
V
CC
(V)
T
A
= 25C
-40 to 85C
-55 to 125C
Min.
Typ.
Max.
Min.
Max.
Min.
Max.
V
IH
High Level Input
Voltage
2.0
1.5
1.5
1.5
V
3.0 to
5.5
0.7V
CC
0.7V
CC
0.7V
CC
V
IL
Low Level Input
Voltage
2.0
0.5
0.5
0.5
V
3.0 to
5.5
0.3V
CC
0.3V
CC
0.3V
CC
V
OH
High Level Output
Voltage
2.0
I
O
=-50
A
1.9
2.0
1.9
1.9
V
3.0
I
O
=-50
A
2.9
3.0
2.9
2.9
4.5
I
O
=-50
A
4.4
4.5
4.4
4.4
3.0
I
O
=-4 mA
2.58
2.48
2.4
4.5
I
O
=-8 mA
3.94
3.8
3.7
V
OL
Low Level Output
Voltage
2.0
I
O
=50
A
0.0
0.1
0.1
0.1
V
3.0
I
O
=50
A
0.0
0.1
0.1
0.1
4.5
I
O
=50
A
0.0
0.1
0.1
0.1
3.0
I
O
=4 mA
0.36
0.44
0.55
4.5
I
O
=8 mA
0.36
0.44
0.55
I
OZ
High Impedance
Output Leakage
Current
5.5
V
I
= V
IH
or V
IL
V
O
= V
CC
or GND
0.25
2.5
2.5
A
I
I
Input Leakage
Current
0 to
5.5
V
I
= 5.5V or GND
0.1
1
1
A
I
CC
Quiescent Supply
Current
5.5
V
I
= V
CC
or GND
4
40
40
A
74VHC257
5/14
Table 7: AC Electrical Characteristics (Input t
r
= t
f
= 3ns)
(*) Voltage range is 3.3V
0.3V
(**) Voltage range is 5.0V
0.5V
Table 8: Capacitive Characteristics
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
/4 (per
channel)
Symbol
Parameter
Test Condition
Value
Unit
V
CC
(V)
C
L
(pF)
T
A
= 25C
-40 to 85C
-55 to 125C
Min.
Typ.
Max.
Min.
Max.
Min.
Max.
t
PLH
t
PHL
Propagation Delay
Time A, B to Y
3.3
(*)
15
5.8
9.3
1.0
11.0
1.0
11.0
ns
3.3
(*)
50
8.3
12.8
1.0
14.5
1.0
14.5
5.0
(**)
15
3.6
5.9
1.0
7.0
1.0
7.0
5.0
(**)
50
5.1
7.9
1.0
9.0
1.0
9.0
t
PLH
t
PHL
Propagation Delay
Time
SELECT to Y
3.3
(*)
15
7.0
11.0
1.0
13.0
1.0
13.0
ns
3.3
(*)
50
9.5
14.5
1.0
16.5
1.0
16.5
5.0
(**)
15
4.0
6.8
1.0
8.0
1.0
8.0
5.0
(**)
50
5.5
8.8
1.0
10.0
1.0
10.0
t
PZL
t
PZH
Output Enable
Time
3.3
(*)
15
R
L
= 1K
6.7
10.5
1.0
12.5
1.0
12.5
ns
3.3
(*)
50
R
L
= 1K
9.2
14.0
1.0
16.0
1.0
16.0
5.0
(**)
15
R
L
= 1K
3.6
6.8
1.0
8.0
1.0
8.0
5.0
(**)
50
R
L
= 1K
5.1
8.8
1.0
10.0
1.0
10.0
t
PLZ
t
PHZ
Output Disable
Time
3.3
(*)
50
R
L
= 1K
8.6
12.0
1.0
13.5
1.0
13.5
ns
5.0
(**)
50
R
L
= 1K
5.7
7.9
1.0
9.0
1.0
9.0
Symbol
Parameter
Test Condition
Value
Unit
T
A
= 25C
-40 to 85C
-55 to 125C
Min.
Typ.
Max.
Min.
Max.
Min.
Max.
C
IN
Input Capacitance
6
10
10
10
pF
C
OUT
Output
Capacitance
8
pF
C
PD
Power Dissipation
Capacitance
(note 1)
18
pF
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