Document
FST3257 — Quad 2:1 Multiplexer / Demultiplexer Bus Switch
May 2009
FST3257 Quad 2:1 Multiplexer / Demultiplexer Bus Switch
Features
4Ω Switch Connection Between Two Ports Minimal Propagation Delay Through the Switch Low ICC Zero Bounce in Flow-Through Node Control Inputs Compatible with TTL Level
Description
The Fairchild Switch FST3257 is a quad 2:1 high-speed CMOS TTL-compatible multiplexer / demultiplexer bus switch. The low on resistance of the switch allows inputs to be connected to outputs without adding propagation delay or generating additional ground bounce noise.
When /OE is LOW, the select pin connects the A port to the selected B port output. When /OE is HIGH, the switch is OPEN and a high-impedance state exists between the two ports.
Ordering Information
Operating Part Number Temperature
Range
FST3257M -40 to 85°C FST3257MX -40 to 85°C FST3257QSC -40 to 85°C FST3257QSCX -40 to 85°C FST3257MTC -40 to 85°C FST3257MTCX -40 to 85°C
Eco Status
Package
RoHS Green RoHS
16-Lead Small Outline Integrated Circuit (SOIC) JEDEC MS-012,0.150 Narrow
16-Lead Quarter Size Outline Package (QSOP) JEDEC MO-137 0.150 Inch Wide
16-Lead Thin Shrink Small Outline Package (TSSOP) JEDEC MO-153, 4mm Wide
Packing Method
Tubes Tape and Reel
Tubes Tape and Reel
Tubes Tape and Reel
For Fairchild’s definition of Eco Status, please visit: http://www.fairchildsemi.com/company/green/rohs_green.html.
© 1997 Fairchild Semiconductor Corporation FST3257 • Rev. 1.0.3
www.fairchildsemi.com
FST3257 — Quad 2:1 Multiplexer / Demultiplexer Bus Switch
Pin Assignments
Figure 1. Logic Diagram
Figure 2. Connection Diagram
Pin Descriptions
Pin # 1
2, 3, 5, 6, 10, 11, 13, 14 4, 7, 9, 12 8 15 16
Truth Table
Select Inputs S
Logic Level LOW Logic Level HIGH
Names S
1B1, 1B2 ,2B1, 2B2, 3B1, 3B2, 4B1, 4B2 1A, 2A, 3A, 4A GND /OE VCC
Bus Switch Enabled Logic Level HIGH Logic Level LOW Logic Level LOW
Description Select Input
Bus B Bus A Ground Bus Switch Enables Supply Voltage
Function Disconnected
A=B1 A=B2
© 1997 Fairchild Semiconductor Corporation
FST3257 • Rev. 1.0.3
2
www.fairchildsemi.com
FST3257 — Quad 2:1 Multiplexer / Demultiplexer Bus Switch
Absolute Maximum Ratings
Stresses exceeding the absolute maximum ratings may damage the device. The device may not function or be operable above the recommended operating conditions and stressing the parts to these levels is not recommended. In addition, extended exposure to stresses above the recommended operating conditions may affect device reliability. The absolute maximum ratings are stress ratings only.
Symbol
Parameter
Min.
Max.
Unit
VCC
Supply Voltage
-0.5
+7.0
V
VS
DC Switch Voltage
VIN
DC Input Voltage(1)
-0.5
+7.0
V
-0.5
+7.0
V
IIK
DC Input Current
-50
mA
IOUT
DC Output Sink Current
128
mA
ICC/IGND
DC VCC/GND Current
±100
mA
TSTG
Storage Temperature Range
-65
+150
°C
Note: 1. The input and output negative voltage ratings may be exceeded if the input and output diode current ratings are
observed.
Recommended Operating Conditions
The Recommended Operating Conditions table defines the conditions for actual device operation. Recommended operating conditions are specified to ensure optimal performance to the datasheet specifications. Fairchild does not recommend exceeding them or designing to Absolute Maximum Ratings.
Symbol
Parameter
Min.
VCC
Power Supply Operating
3.0
VIN
Input Voltage
0
VOUT
Output Voltage
0
Switch Control Input
0
tr,tf
Input Rise and Fall Time
Switch I/O
0
TA
Free Air Operating Temperature
-40
Note: 2. Unused control inputs must be held HIGH or LOW. They may not float.
Max. 5.5 5.5 5.5 5 DC +85
Unit V V V
ns/V
°C
© 1997 Fairchild Semiconductor Corporation
FST3257 • Rev. 1.0.3
3
www.fairchildsemi.com
FST3257 — Quad 2:1 Multiplexer / Demultiplexer Bus Switch
DC Electrical Characteristics
Symbol
Parameter
Conditions
VCC (V)
TA=-40 to +85°C Units
Min. Typ.(3) Max.
VIK
Clamp Diode Voltage
IIN=-18mA
VIH
High-Level Input Voltage
VIL
Low-Level Input Voltage
4.5 3.0 to 3.6(5) 1.8 4.0 to 5.5 2.0 3.0 to 3.6(5) 4.0 to 5.5
-1.2
V
V
0.7 V
0.8
IIN
Input Leakage Current
0 ≤ VIN ≤ 5.5
5.5
±1.0 µA
IOZ
Off-state Leakage Current 0 ≤ A, B ≤ VCC
VIN=0V, IIN=64mA
VIN=0V, IIN=30mA
VIN=2.4V, IIN=15mA
RON
Switch On Resistance(4)
VIN=2.4V, IIN=15mA VIN=0V, IIN=64mA
5.5 3.3(5) 3.3(5) 3.3(5) 3.0(5)
4.5
±1.0 µA
13
20
28
40
200
230
210
250
Ω
4
7
VIN=0V, IIN=30mA
4.5
4
7
VIN=2.4V, IIN=15mA
4.5
8
15
VIN=2.4V, IIN=15mA
4.0
11
20
ICC
Quiescent Supply Current
VIN=VCC or GND, IOUT=0,
5.5
3
µA
ΔICC Increase in ICC per input
One Input at 3.4V, Other inputs at VCC or GND
5.5
2.5
mA
Notes: 3. Typical values are at nominal VCC for the VCC range and TA=25°C. 4. 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 th.