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Электронный компонент: 74VHCT257ATTR

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74VHCT257A
QUAD 2 CHANNEL MULTIPLEXER (3-STATE)
PRELIMINARY DATA
March 2000
s
HIGH SPEED: t
PD
= 5.8 ns (TYP.) at V
CC
= 5V
s
LOWPOWER DISSIPATION:
I
CC
= 4
A (MAX.) at T
A
= 25
o
C
s
COMPATIBLE WITH TTL OUTPUTS:
V
IH
= 2V (MIN), V
IL
= 0.8V (MAX)
s
POWER DOWN PROTECTION ON INPUTS &
OUTPUTS
s
SYMMETRICAL OUTPUT IMPEDANCE:
|I
OH
| = I
OL
= 8 mA (MIN)
s
BALANCED PROPAGATION DELAYS:
t
PLH
t
PHL
s
OPERATING VOLTAGE RANGE:
V
CC
(OPR) = 4.5V to 5.5V
s
PIN AND FUNCTION COMPATIBLE WITH
74 SERIES 257
s
IMPROVED LATCH-UP IMMUNITY
s
LOWNOISE: V
OLP
= 0.8V (Max.)
DESCRIPTION
The 74VHCT257A 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
INPUT.
The 74VHCT257A is a non inverting multiplexer.
When the ENABLE INPUT is held "High", all
outputs
become
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 output 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.
PIN CONNECTION AND IEC LOGIC SYMBOLS
SOP
TSSOP
ORDER CODES
PACKAGE
T UBE
T & R
SOP
74VHCT257AM
74VHCT257AMTR
TSSOP
74VHCT257ATTR
1/9
INPUT EQUIVALENT CIRCUIT
LOGIC DIAGRAM
PIN DESCRIPTION
PIN No
SYMBOL
NAME AND FUNCT ION
1
SELECT
Common Data Select Input
2, 5, 14, 11
1A to 4A
Data Inputs from Source A
3, 6, 13, 10
1B to 4B
Data Inputs from Source B
4, 7, 12, 9
1Y to 4Y
3 State Multiplexer Outputs
15
OE
3 State Output Enable
Input (Active LOW)
8
GND
Ground (0V)
16
V
CC
Positive Supply Voltage
TRUTH TABLE
INPUT S
OUTPUTS
OE
SELE CT
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
X = DON'T CARE Z = HIGH IMPEDANCE
Thislogic diagram has notbe used to estimate propagation delays
74VHCT257A
2/9
RECOMMENDED OPERATING CONDITIONS
Symbol
Parameter
Valu e
Uni t
V
CC
Supply Voltage
4.5 to 5.5
V
V
I
Input Voltage
0 to 5.5
V
V
O
Output Voltage (see note 1)
0 to 5.5
V
V
O
Output Voltage (see note 2)
0 to V
CC
V
T
op
Operating Temperature
-40 to +85
o
C
dt/dv
Input Rise and Fall Time (see note 3) (V
CC
= 5.0
0.5V)
0 to 20
ns/V
1) Output in OFF State
2) High or Low State
3)V
IN
from0.8V to 2 V
ABSOLUTE MAXIMUM RATINGS
Symbol
Parameter
Val ue
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 (see note 1)
-0.5 to +7.0
V
V
O
DC Output Voltage (see note 2)
-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
o
C
T
L
Lead Temperature (10 sec)
300
o
C
Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these condition is not implied.
1) Output in OFF State
2) High or Low State
74VHCT257A
3/9
DC SPECIFICATIONS
Symb ol
Parameter
T est Cond ition s
Val ue
Un it
V
CC
(V)
T
A
= 25
o
C
-40 to 85
o
C
Min.
Typ .
Max.
Min .
Max.
V
IH
High Level Input
Voltage
4.5 to 5.5
2
2
V
V
IL
Low Level Input
Voltage
4.5 to 5.5
0.8
0.8
V
V
OH
High Level Output
Voltage
4.5
I
O
=-50
A
4.4
4.5
4.4
V
4.5
I
O
=-8 mA
3.94
3.8
V
OL
Low Level Output
Voltage
4.5
I
O
=50
A
0.0
0.1
0.1
V
4.5
I
O
=8 mA
0.36
0.44
I
OZ
High Impedance
Output Leakage
Current
4.5 to 5.5
V
I
= V
IH
or V
IL
V
O
= 0V to 5.5V
0.25
2.5
A
I
I
Input Leakage Current
0 to 5.5
V
I
= 5.5V or GND
0.1
1.0
A
I
CC
Quiescent Supply
Current
5.5
V
I
= V
CC
or GND
4
40
A
I
CC
Additional Worst Case
Supply Current
5.5
One Input at 3.4V,
other input at V
CC
or
GND
1.35
1.5
mA
I
OPD
Output Leakage
Current
0
V
OUT
= 5.5V
0.5
5.0
A
AC ELECTRICAL CHARACTERISTICS (Input t
r
= t
f
=3 ns)
Symb ol
Parameter
Test Co nditi on
Val ue
Un it
V
CC
(V)
C
L
(pF )
T
A
= 25
o
C
-40 to 85
o
C
Min.
Typ .
Max.
Min .
Max.
t
PLH
t
PHL
Propagation Delay
Time A, B to Y
5.0
(*)
15
5.8
9.3
1.0
11.0
ns
5.0
(*)
50
8.3
12.8
1.0
14.5
t
PLH
t
PHL
Propagation Delay
Time SELECT to Y
5.0
(*)
15
7.0
11.0
1.0
13.0
ns
5.0
(*)
50
9.5
14.5
1.0
16.5
t
PZL
t
PZH
Output Enable Time
5.0
(*)
15
6.7
10.5
1.0
12.5
ns
5.0
(*)
50
9.2
14.0
1.0
16.0
t
PLZ
t
PHZ
Output Disable Time
5.0
(*)
50
8.6
12.0
1.0
13.5
ns
(*) Voltage range is 5V
0.5V
74VHCT257A
4/9
CAPACITIVE CHARACTERISTICS
Symb ol
Parameter
T est Cond ition s
Val ue
Un it
T
A
= 25
o
C
-40 to 85
o
C
Min.
Typ .
Max.
Min .
Max.
C
IN
Input Capacitance
4
10
10
pF
C
OUT
Output Capacitance
6
pF
C
PD
Power Dissipation
Capacitance (note 1)
23
pF
1) C
PD
isdefined as the value of the IC'sinternal equivalent capacitance which is calculated fromthe operating current consumption without load. (Referto
Test Circuit).Average operating current can be obtained by the following equation. I
CC
(opr) = C
PD
V
CC
f
IN
+ I
CC
/4 (per Channel)
DYNAMIC SWITCHING CHARACTERISTICS
Symb ol
Parameter
T est Cond ition s
Val ue
Un it
V
CC
(V)
T
A
= 25
o
C
-40 to 85
o
C
Min.
Typ .
Max.
Min .
Max.
V
OLP
Dynamic Low Voltage
Quiet Output (note 1, 2)
5.0
C
L
= 50 pF
0.3
0.8
V
V
OLV
-0.8
-0.3
V
IHD
Dynamic High Voltage
Input (note 1, 3)
5.0
2.0
V
IL D
Dynamic Low Voltage
Input (note 1, 3)
5.0
0.8
1) Worst case package.
2) Max number of outputs defined as (n). Data inputs are driven 0V to 3.0V, (n -1) outputs switching and one output at GND.
3) Max number of data inputs (n) switching. (n-1) switching 0V to3.0V. Inputs under test switching: 3.0V to threshold (V
ILD
), 0V to threshold (V
IHD
), f=1MHz.
TEST CIRCUIT
T EST
SW IT CH
t
PLH
, t
PHL
Open
t
PZL
, t
PLZ
V
CC
t
PZH
, t
PHZ
GND
C
L
= 15/50 pF or equivalent (includes jig and probe capacitance)
R
L
= R
1
= 1K
orequivalent
R
T
= Z
OUT
of pulse generator (typically 50
)
74VHCT257A
5/9