74VHCT257A
Quad 2 channel multiplexer (3-state)
Datasheet
−
production data
Features
■
■
■
■
■
■
■
■
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■
High speed: t
PD
= 4.8 ns (typ.) at V
CC
= 5 V
I
Low power dissipation
CC
= 4 μ A (max.) at T
A
= 25 °C
Compatible with TTL outputs
V
IH
= 2 V (min.), V
IL
= 0.8 V (max.)
Power-down protection on inputs and outputs
Symmetrical output impedance
|I
OH
| = I
OL
= 8 mA (min.)
Balanced propagation delays: t
PLH
≅ t
PHL
Operating voltage range: V
CC(opr)
= 4.5 to 5.5 V
Pin and function compatible with 74 series 257
Improved latch-up immunity
Low noise: V
OLP
= 0.8 V (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
(OE). The VHCT257A is a non-inverting multiplexer.
Figure 1.
Pin connection and IEC logic symbols
SO-16
Table 1.
Order code
Package
SO-16
Tape and reel
74VHCT257AMTR
When the enable input is held “high”, all outputs become high impedance state. If the 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 outputs and 0 to 7 V can be accepted on inputs with no regard to the supply voltage. This device can be used to interface 5 V to 3 V since all inputs are equipped with TTL threshold.
All inputs and outputs are equipped with protection circuits against static discharge, giving them 2 KV ESD immunity and transient excess voltage.
Obsolete Product(s) - Obsolete Product(s)
November 2012
This is information on a product in full production.
Doc ID 7073 Rev 4 1/15 www.st.com
1
Input equivalent circuit
1 Input equivalent circuit
Figure 2.
Input equivalent circuit
74VHCT257A
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2/15 Doc ID 7073 Rev 4
74VHCT257A Pin settings
Table 2.
Pin No
Pin description
Symbol
1
2, 5, 11, 14
3, 6, 10, 13
4, 7, 9, 12
15
8
16
SELECT
1A to 4A
1B to 4B
1Y to 4Y
OE
GND
V
CC
Table 3.
Truth table
Inputs
OE
H
L
L
L
L
1.
“Don’t care”.
2.
High impedance.
SELECT
X
(1)
L
L
H
H
A
X
(1)
L
H
X
(1)
X
(1)
Name and function
Common data select inputs
Data inputs from source A
Data inputs from source B
3-state multiplexer outputs
3-state output enable inputs (active LOW)
Ground (0 V)
Positive supply voltage
B
X
(1)
X
(1)
X
(1)
L
H
Output
Y
Z
(2)
L
H
L
H
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Pin settings
Figure 3.
Logic diagram
3%,%#4
!
"
!
"
/%
"
!
"
!
1.
This logic diagram has not be used to estimate propagation delays.
/%
3
9
9
9
9
74VHCT257A
!-
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4/15 Doc ID 7073 Rev 4
74VHCT257A Maximum ratings
Table 4.
Symbol
Absolute maximum ratings
Parameter Value Unit
V
CC
V
I
V
O
V
O
Supply voltage
DC input voltage
DC output voltage
(1)
DC output voltage
(2)
-0.5 to +7.0
-0.5 to +7.0
-0.5 to +7.0
V
V
V
I
IK
I
OK
I
O
I
CC
or
I
GND
T stg
DC input diode current
DC output diode current
DC output current
DC V
CC
or ground current
Storage temperature
-0.5 to V
CC
+ 0.5
- 20
±
20
±
25
±
50
-65 to +150
V mA mA mA mA
°C
T
L
Lead temperature (10 sec.) 300
1.
Absolute maximum ratings are those values beyond which damage to the device may occur. Functional operation under these conditions is not implied: output in OFF state.
2.
Absolute maximum ratings are those values beyond which damage to the device may occur. Functional operation under these conditions is not implied: high or low state.
°C
Table 5.
Symbol
Recommended operating conditions
Parameter Value Unit
V
CC
Supply voltage
V
I
V
O
Input voltage
Output voltage
(1)
V
O
Output voltage
(2)
T op
Operating temperature dt/dv Input rise and fall time
(3)
(V
CC
= 5.0
±
0.5 V)
4.5 to 5.5
0 to 5.5
0 to 5.5
0 to V
CC
-55 to 125
0 to 20
1.
Output in OFF state.
2.
High or low state.
3.
V
IN
from 0.8 V to 2 V.
Obsolete Product(s) - Obsolete Product(s)
V
V
V
V
°C ns/V
Doc ID 7073 Rev 4 5/15
Electrical characteristics 74VHCT257A
Table 6.
DC specifications
Test condition Value
Symbol
I
+
I
I
V
V
V
V
I
OZ
I
IH
IL
OH
OL
I
CC
CC
OPD
Parameter
V
CC
(V)
T
A
= 25 °C -40 to 85 °C -55 to 125 °C
Min. Typ.
Max.
Min.
Max.
Min.
Max.
Unit
High level input voltage
Low level input voltage
4.5 to 5.5
4.5 to 5.5
2
0.8
High level output voltage
Low level output voltage
4.5
4.5
4.5
4.5
I
O
= -50
μ
A
I
O
= -8 mA
I
O
= 50
μ
A
I
O
= 8 mA
High impedance output leakage current
Input leakage current
Quiescent supply current
Additional worst case supply current
Output leakage current
5.5
5.5
5.5
0
V
V
I
V
O
I
= V
IH
= V
or V
IL
= 0 V to 5.5 V
0 to 5.5
V
I
= 5.5 V or GND
One input at
3.4 V, other input at V
CC or GND
V
CC
OUT
or GND
= 5.5 V
4.4
4.5
3.94
0.0
0.1
0.36
±
±
0.25
0.1
4
1.35
0.5
2
4.4
3.8
±
±
0.8
0.1
0.44
2.5
1.0
40
1.5
5.0
2
4.4
3.7
0.1
0.55
±
±
0.8
2.5
1.0
40
1.5
5.0
V
V
V
V
μ
μ
μ mA
μ
A
A
A
A
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74VHCT257A Electrical characteristics
Table 7.
AC electrical characteristics (input t r
= t f
= 3 ns )
Test condition Value
Symbol t t t t
PLH t
PHL
Propagation delay time A, B, to Y
PLH
PHL t
PZL
PZH
Parameter
Propagation delay time
SELECT to Y
Output enable time t
PLZ t
PHZ
Output disable time
1.
Voltage range is 5.0 V ± 0.5 V.
T
A
= 25 °C -40 to 85 °C -55 to 125 °C Unit
V
CC
(1)
(V) C
L
(pF)
Min. Typ. Max. Min.
Max.
Min.
Max.
5.0
5.0
5.0
5.0
5.0
5.0
15
50
15
50
15
50
4.8
5.5
6.0
7.0
7.0
8.0
6.8
8.8
1.0
1.0
1.0
1.0
8.0
9.0
8.0
10.0
1.0
1.0
1.0
1.0
5.8
6.8
1.0
8.0
1.0
8.0
9.0
8.0
10.0
8.0
6.5
8.8
1.0
10.0
1.0
10.0
ns ns ns
5.0
50 5.7
7.9
1.0
9.0
1.0
9.0
ns
Table 8.
Capacitive characteristics
Test condition Value
Symbol Parameter T
A
= 25 °C -40 to 85 °C -55 to 125 °C
Min. Typ. Max. Min.
Max.
Min.
Max.
C
C
C
IN
OUT
PD
Input capacitance
Output capacitance
Power dissipation capacitance
(1)
4
6
23
10 10 10
1.
CPD is defined as the value of the IC’s internal equivalent capacitance which is calculated from the operating current
consumption without load. (Refer to Figure 5: Test circuit ). Average operating current can be obtained by equation:
I
CC(opr)
= C
PD
x V
CC
x f
IN
+ I
CC
/4 (per channel).
Unit pF pF pF
Table 9.
Dynamic switching characteristics
Test condition Value
Symbol Parameter T
A
= 25 °C -40 to 85 °C -55 to 125 °C
V
CC
V
OLP
(V)
Min. Typ. Max. Min.
Max.
Min.
Max.
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Dynamic low voltage quiet
5.0
0.3
0.8
output
(1)
,
(2)
V
OLV
-0.8
-0.3
C
L
= 50 pF
V
IHD
Dynamic high voltage input
(1)
,
(3)
5.0
2.0
V
Unit
Dynamic low voltage input
(1)
,
(3)
V
ILD
5.0
0.8
1.
Worst case package.
2.
Max. number of outputs defined as (n). Data inputs are driven 0 V to 3.0 V, (n-1) outputs switching and one output at GND.
3.
Max. number of data inputs (n) switching. (n-1) switching 0 V to 3.0 V. Inputs under test switching: 3.0 V to threshold (V
ILD
0 V to threshold (V
IHD
), f = 1 MHz.
),
Doc ID 7073 Rev 4 7/15
74VHCT257A Test circuit
Figure 4.
Test circuit
Table 10.
Switch configuration
Input Load Switch
Type
74VHCT257
V
I
3 V t r
, t f
6 ns
C
L
50 pF
R
L t
PHL
, t
PLH t
PZH
, t
PHZ t
PZL
, t
1 k
Ω
Open GND V
CC
PLZ
C
L
= 15/ 50 pF or equivalent (includes jig and probe capacitance).
R
L
= R
1
= 1 K Ω or equivalent.
R
T
= Z
OUT
of pulse generator (typically 50 Ω ).
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8/15 Doc ID 7073 Rev 4
74VHCT257A
6 Waveforms
Figure 5.
Waveform - propagation delays for inverting conditions
(f = 1 mhz; 50% duty cycle)
Waveforms
Figure 6.
Waveform - propagation delays for non-inverting conditions
(f = 1 MHz; 50% duty cycle)
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Doc ID 7073 Rev 4 9/15
Waveforms 74VHCT257A
Figure 7.
Waveform - output enable and disable time (f = 1 MHz; 50% duty cycle)
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10/15 Doc ID 7073 Rev 4
74VHCT257A Package information
In order to meet environmental requirements, ST offers these devices in different grades of
ECOPACK
®
packages, depending on their level of environmental compliance. ECOPACK specifications, grade definitions and product status are available at: www.st.com
. ECOPACK is an ST trademark.
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Doc ID 7073 Rev 4 11/15
Package information
Figure 8.
SO-16 package outline
74VHCT257A
12/15
% b1
C c1
D
A a1 a2 b
Table 11.
SO-16 mechanical data
Symbol
Min.
0.1
0.35
0.19
Dimensions mm inch
Typ.
Max. Min. Typ. Max.
1.75 0.068
0.25 0.004 0.010
1.64 0.063
0.46 0.013 0.018
0.25 0.007
0.5 0.019
0.010
45° (typ.) e e3
F
G
L
M
S
1.27 0.050
8.89 0.350
0.62 0.024
8° (max.)
Doc ID 7073 Rev 4
74VHCT257A
Figure 9.
SO-16 tape and reel
Package information
3/42
1.
drawing not in scale.
Table 12.
SO-16 tape and reel mechanical data
Dimensions
Symbol mm inch
Min.
Typ.
Max. Min. Typ. Max.
Ao
Bo
Ko
Po
P
A 330 12.992
C
T
12.8 13.2
0.504
D
N
20.2 0.795
2.362
0.519
22.4 0.882
6.45
10.3
2.1
3.9
7.9
6.65 0.254
10.5
0.262
0.406 0.414
2.3
4.1
8.1
0.082 0.090
0.153 0.161
0.311
0.319
Doc ID 7073 Rev 4 13/15
Revision history
Revision history
74VHCT257A
Table 13.
Document revision history
Date Revision
16-Dec-2004
21-Nov-2012
3
4
Changes
Order Codes Revision - pag. 1.
Removed 74VHCT257ATTR device and TSSOP package from document.
Replaced SOP by SO16 package on page 1.
Added numbered headings to Section 1: Input equivalent circuit
to
Section 7: Package information
.
Updated
Table 10
(removed 74HC257 device, 74HCT257 replaced by 74VHCT257 device).
Updated
Section 7: Package information
, added ECOPACK
®
.
Minor text corrections throughout document.
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74VHCT257A
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