FST3125 Datasheet, PDF (1/6 Pages) Fairchild Semiconductor – Quad Bus Switch

August 1997
Revised December 1999
FST3125
Quad Bus Switch
General Description
The Fairchild Switch FST3125 provides four high-speed
CMOS TTL-compatible bus switches. The low on resis-
tance of the switch allows inputs to be connected to out-
puts without adding propagation delay or generating
additional ground bounce noise.
The device is organized as four 1-bit switches with sepa-
rate OE inputs. When OE is LOW, the switch is ON and
Port A is connected to Port B. When OE is HIGH, the
switch is OPEN and a high-impedance state exists
between the two ports.
Features
s 4Ω switch connection between two ports.
s Minimal propagation delay through the switch.
s Low l_CC.
s Zero bounce in flow-through mode.
s Control inputs compatible with TTL level.
Ordering Code:
Order Number
FST3125M
FST3125QSC
Package Number
Package Description
M14A
14-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-120, 0.150 Narrow
MQA16
16-Lead Quarter Size Outline Package (QSOP), JEDEC MO-137, 0.150 Wide
FST3125MTC
MTC14
14-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mm Wide
Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering code.
Logic Diagram
Connection Diagrams
Pin Assignment for SOIC and TSSOP
Pin Assignment for QSOP
Pin Descriptions
Pin Name
OE₁, OE₂, OE₃, OE₄
1A, 2A, 3A, 4A
1B, 2B, 3B, 4B
NC
Description
Bus Switch Enables
Bus A
Bus B
Not Connected
Truth Table
Inputs
OE
L
H
© 1999 Fairchild Semiconductor Corporation DS500043
Inputs/Outputs
A,B
A=B
Z
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