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74FST3257
Quad 2:1 Multiplexer/
Demultiplexer Bus Switch
The ON Semiconductor 74FST3257 is a quad 2:1, high performance
multiplexer/demultiplexer bus switch. The device is CMOS TTL
compatible when operating between 4 and 5.5 Volts. The device
exhibits extremely low R
ON
and adds nearly zero propagation delay.
The device adds no noise or ground bounce to the system.
Features
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MARKING
DIAGRAMS
16
1
SOIC−16
D SUFFIX
CASE 751B
16
1
TSSOP−16
DT SUFFIX
CASE 948F
FST
3257
ALYW
G
G
1
16
1
QSOP−16
QS SUFFIX
CASE 492
S3257
ALYW
1
16
FST3257G
AWLYWW
1
16
•
•
•
•
•
•
•
•
R
ON
t
4
W
Typical
Less Than 0.25 ns−Max Delay Through Switch
Nearly Zero Standby Current
No Circuit Bounce
Control Inputs are TTL/CMOS Compatible
Pin−For−Pin Compatible With QS3257, FST3257, CBT3257
All Popular Packages: SOIC−16, TSSOP−16, QSOP−16, QFN16
Pb−Free Packages are Available
S V
CC
1 16
S
1B
1
1B
2
1A
2B
1
2B
2
2A
GND
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
V
CC
OE
4B
1
4B
2
4A
3B
1
3B
2
3A
1B
1
1B
2
1A
2B
1
2B
2
2A
2
3
4
5
6
7
GND
8 9
GND 3A
15
14
13
12
11
10
OE
4B
1
4B
2
4A
3B
1
3B
2
16
Figure 1. 16−Lead Pinout Diagrams
S
X
L
H
OE
H
L
L
Function
Disconnect
A = B
1
A = B
2
1
QFN16
MN SUFFIX
CASE 485AW
A
WL, L
Y
WW, W
G
3257
ALYWG
G
= Assembly Location
= Wafer Lot
= Year
= Work Week
= Pb−Free Package
Figure 2. Truth Table
(Note: Microdot may be in either location)
PIN NAMES
Pin
OE
1
, OE
2
S
0
, S
1
A
B
1
, B
2
, B
3
, B
4
Description
Bus Switch Enables
Select Inputs
Bus A
Bus B
ORDERING INFORMATION
See detailed ordering and shipping information in the package
dimensions section on page 2 of this data sheet.
©
Semiconductor Components Industries, LLC, 2008
December, 2008
−
Rev. 5
1
Publication Order Number:
74FST3257/D
74FST3257
1A
1B
1B
2
2A
2B
1
2B
2
3A
3B
1
3B
2
4A
4B
1
4B
2
FLOW CONTROL
OE
S
Figure 3. Logic Diagram
ORDERING INFORMATION
Device Order Number
74FST3257D
74FST3257DR2
74FST3257DR2G
74FST3257DT
74FST3257DTR2
74FST3257DTR2G
74FST3257QSR
74FST3257MNTWG
Package
SOIC−16
SOIC−16
SOIC−16
(Pb−Free)
TSSOP−16*
TSSOP−16*
TSSOP−16*
(Pb−Free)
QSOP−16
QFN16
(Pb−Free)
Shipping
†
48 Units / Rail
2500 Units / Tape & Reel
2500 Units / Tape & Reel
96 Units / Rail
2500 Units / Tape & Reel
2500 Units / Tape & Reel
2500 Units / Tape & Reel
3000 Units / Tape & Reel
†For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging
Specifications Brochure, BRD8011/D.
*This package is inherently Pb−Free.
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2
74FST3257
MAXIMUM RATINGS
Symbol
V
CC
V
I
V
O
I
IK
I
OK
I
O
I
CC
I
GND
T
STG
T
L
T
J
q
JA
DC Supply Voltage
DC Input Voltage
DC Output Voltage
DC Input Diode Current
DC Output Diode Current
DC Output Sink Current
DC Supply Current per Supply Pin
DC Ground Current per Ground Pin
Storage Temperature Range
Lead Temperature, 1 mm from Case for 10 Seconds
Junction Temperature Under Bias
Thermal Resistance
SOIC
TSSOP
QSOP
QFN
V
I
t
GND
V
O
t
GND
Parameter
Value
*0.5
to
)7.0
*0.5
to
)7.0
*0.5
to
)7.0
*50
*50
128
$100
$100
*65
to
)150
260
)150
125
170
200
TBD
Level 1
Oxygen Index: 28 to 34
Human Body Model (Note 1)
Machine Model (Note 2)
Charged Device Model (Note 3)
Above V
CC
and Below GND at 85_C (Note 4)
UL 94 V−0 @ 0.125 in
u2000
u200
N/A
$500
V
Unit
V
V
V
mA
mA
mA
mA
mA
_C
_C
_C
_C/W
MSL
F
R
V
ESD
Moisture Sensitivity
Flammability Rating
ESD Withstand Voltage
I
Latchup
Latchup Performance
mA
Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the
Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect
device reliability.
1. Tested to EIA/JESD22−A114−A.
2. Tested to EIA/JESD22−A115−A.
3. Tested to JESD22−C101−A.
4. Tested to EIA/JESD78.
RECOMMENDED OPERATING CONDITIONS
Symbol
V
CC
V
I
V
O
T
A
Dt/DV
Supply Voltage
Input Voltage
Output Voltage
Operating Free−Air Temperature
Input Transition Rise or Fall Rate
Switch I/O
Switch Control Input
V
CC
= 5.0 V
$
0.5 V
Parameter
Operating, Data Retention Only
(Note 5)
(HIGH or LOW State)
Min
4.0
0
0
*40
0
Max
5.5
5.5
5.5
)85
DC
5
Unit
V
V
V
_C
ns/V
5. Unused control inputs may not be left open. All control inputs must be tied to a high or low logic input voltage level.
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3
74FST3257
DC ELECTRICAL CHARACTERISTICS
V
CC
Symbol
V
IK
V
IH
V
IL
I
I
I
OZ
R
ON
Parameter
Clamp Diode Voltage
High−Level Input Voltage
Low−Level Input Voltage
Input Leakage Current
Off−State Leakage Current
Switch On Resistance (Note 6)
0
v
V
IN
v
5.5 V
0
v
A, B
v
V
CC
V
IN
= 0 V, I
IN
= 64 mA
V
IN
= 0 V, I
IN
= 30 mA
V
IN
= 2.4 V, I
IN
= 15 mA
V
IN
= 2.4 V, I
IN
= 15 mA
I
CC
DI
CC
Quiescent Supply Current
Increase In I
CC
per Input
V
IN
= V
CC
or GND, I
OUT
= 0
One input at 3.4 V,
Other inputs at V
CC
or GND
Conditions
I
IN
=
*18mA
(V)
4.5
4.0 to 5.5
4.0 to 5.5
5.5
5.5
4.5
4.5
4.5
4.0
5.5
5.5
4
4
8
11
2.0
0.8
$1.0
$1.0
7
7
15
20
3
2.5
mA
mA
T
A
=
*40_C
to
)85_C
Min
Typ*
Max
*1.2
Unit
V
V
V
mA
mA
W
*Typical values are at V
CC
= 5.0 V and T
A
= 25_C.
6. Measured by the voltage drop between A and B pins at the indicated current through the switch. On resistance is determined by the lower
of the voltages on the two (A or B) pins.
AC ELECTRICAL CHARACTERISTICS
T
A
=
*40_C
to
)85_C
C
L
= 50 pF, RU = RD = 500
W
V
CC
= 4.5−5.5 V
Symbol
t
PHL
,
t
PLH
t
PZH
,
t
PZL
t
PHZ
,
t
PLZ
Parameter
Prop Delay Bus to Bus (Note 7)
Prop Delay, Select to Bus A
Output Enable Time, Select to Bus B
Output Enable Time, I
OE
to Bus A, B
Output Disable Time, Select to Bus B
Output Disable Time, I
OE
to Bus A, B
V
I
= 7 V for t
PZL
V
I
= OPEN for t
PZH
V
I
= 7 V for t
PLZ
V
I
= OPEN for t
PHZ
Conditions
V
I
= OPEN
1.0
1.0
1.0
1.0
1.0
Min
Max
0.25
4.7
5.2
5.1
5.2
5.5
V
CC
= 4.0 V
Min
Max
0.25
5.2
5.7
5.6
5.5
5.5
ns
ns
Unit
ns
7. This parameter is guaranteed by design but is not tested. The bus switch contributes no propagation delay other than the RC delay of the
typical On resistance of the switch and the 50 pF load capacitance, when driven by an ideal voltage source (zero output impedance).
CAPACITANCE
(Note 8)
Symbol
C
IN
C
I/O
C
I/O
Parameter
Control Pin Input Capacitance
A Port Input/Output Capacitance
B Port Input/Output Capacitance
V
CC
= 5.0 V
V
CC
, OE = 5.0 V
V
CC
, OE = 5.0 V
Conditions
Typ
3
7
5
Max
Unit
pF
pF
pF
8. T
A
=
)25_C,
f = 1 MHz, Capacitance is characterized but not tested.
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