74VHC257
QUAD 2 CHANNEL MULTIPLEXER (3-STATE)
s
s
s
s
s
s
s
s
s
s
HIGH SPEED: t
PD
= 3.7ns (TYP.) at V
CC
= 5V
LOW POWER DISSIPATION:
I
CC
= 4
µA
(MAX.) at T
A
=25°C
HIGH NOISE IMMUNITY:
V
NIH
= V
NIL
= 28% V
CC
(MIN.)
POWER DOWN PROTECTION ON INPUTS
SYMMETRICAL OUTPUT IMPEDANCE:
|I
OH
| = I
OL
= 8mA (MIN)
BALANCED PROPAGATION DELAYS:
t
PLH
≅
t
PHL
OPERATING VOLTAGE RANGE:
V
CC
(OPR) = 2V to 5.5V
PIN AND FUNCTION COMPATIBLE WITH
74 SERIES 257
IMPROVED LATCH-UP IMMUNITY
LOW NOISE: V
OLP
= 0.8V (MAX.)
SOP
TSSOP
Table 1: Order Codes
PACKAGE
SOP
TSSOP
T&R
74VHC257MTR
74VHC257TTR
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.
Figure 1: Pin Connection And IEC Logic Symbols
November 2004
Rev. 4
1/14
74VHC257
Table 4: Absolute Maximum Ratings
Symbol
V
CC
V
I
V
O
I
IK
I
OK
I
O
T
stg
T
L
Supply Voltage
DC Input Voltage
DC Output Voltage
DC Input Diode Current
DC Output Diode Current
DC Output Current
Storage Temperature
Lead Temperature (10 sec)
Parameter
Value
-0.5 to +7.0
-0.5 to +7.0
-0.5 to V
CC
+ 0.5
- 20
±
20
±
25
±
50
-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
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
Symbol
V
CC
V
I
V
O
T
op
dt/dv
Supply Voltage
Input Voltage
Output Voltage
Operating Temperature
Input Rise and Fall Time (note 1) (V
CC
= 3.3
±
0.3V)
(V
CC
= 5.0
±
0.5V)
Parameter
Value
2 to 5.5
0 to 5.5
0 to V
CC
-55 to 125
0 to 100
0 to 20
Unit
V
V
V
°C
ns/V
1) V
IN
from 30% to 70% of V
CC
3/14
74VHC257
Table 7: AC Electrical Characteristics
(Input t
r
= t
f
= 3ns)
Test Condition
Symbol
Parameter
V
CC
(V)
3.3
(*)
3.3
(*)
5.0
(**)
5.0
(**)
t
PLH
t
PHL
Propagation Delay
Time
SELECT to Y
3.3
(*)
3.3
(*)
5.0
(**)
5.0
(**)
t
PZL
t
PZH
Output Enable
Time
3.3
(*)
3.3
(*)
5.0
(**)
5.0
(**)
t
PLZ
t
PHZ
Output Disable
Time
3.3
(*)
5.0
(**)
C
L
(pF)
15
50
15
50
15
50
15
50
15
50
15
50
50
50
R
L
= 1K
Ω
R
L
= 1K
Ω
R
L
= 1K
Ω
R
L
= 1K
Ω
R
L
= 1K
Ω
R
L
= 1K
Ω
T
A
= 25°C
Min.
Typ.
5.8
8.3
3.6
5.1
7.0
9.5
4.0
5.5
6.7
9.2
3.6
5.1
8.6
5.7
Max.
9.3
12.8
5.9
7.9
11.0
14.5
6.8
8.8
10.5
14.0
6.8
8.8
12.0
7.9
Value
-40 to 85°C
Min.
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
Max.
11.0
14.5
7.0
9.0
13.0
16.5
8.0
10.0
12.5
16.0
8.0
10.0
13.5
9.0
-55 to 125°C
Min.
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
Max.
11.0
14.5
7.0
9.0
13.0
16.5
8.0
10.0
12.5
16.0
8.0
10.0
13.5
9.0
ns
ns
ns
ns
Unit
t
PLH
t
PHL
Propagation Delay
Time A, B to Y
(*) Voltage range is 3.3V
±
0.3V
(**) Voltage range is 5.0V
±
0.5V
Table 8: Capacitive Characteristics
Test Condition
Symbol
Parameter
T
A
= 25°C
Min.
C
IN
C
OUT
C
PD
Input Capacitance
Output
Capacitance
Power Dissipation
Capacitance
(note 1)
Typ.
6
8
18
Max.
10
Value
-40 to 85°C
Min.
Max.
10
-55 to 125°C
Min.
Max.
10
pF
pF
pF
Unit
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)
5/14
Embedded System
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