March 2008

© 2005 Fairchild Semiconductor Corporation

www.fairchildsemi.com

FST3125 • Rev. 1.0.3

FST3125 — 4-Bit Bus Switch

Features

4

Ω Switch Connection between Two Ports

Minimal Propagation Delay through the Switch

Zero Bounce in Flow-through Mode

Control Inputs Compatible with TTL Level

Description

Fairchild switch FST3125 provides four high-speed

CMOS TTL-compatible bus switches. The low on

resistance of the switch allows inputs to be connected

to

outputs

without

adding

propagation

delay

or

generating additional ground bounce noise.

The device is organized as four one1-bit switches with

separate /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.

Ordering Information

Part Number

Operating

Temperature

Range

Package

Packing

Method

FST3125M

-40 to 85°C

14-Lead, Small Outline Integrated Circuit (SOIC) 0.150 inch

Narrow

Tube

FST3125MX

-40 to 85°C

14-Lead, Small Outline Integrated Circuit (SOIC) 0.150 inch

Narrow

Tape and Reel

FST3125QSC

-40 to 85°C

16-Lead, Quarter Size Outline Package (QSOP) MO-137

0.150 inch Wide

Tube

FST3125QSCX

-40 to 85°C

16-Lead, Quarter Size Outline Package (QSOP) MO-137

0.150 inch Wide

Tape and Reel

FST3125MTC

-40 to 85°C

14-Lead, Thin Shrink Small Outline Package (TSSOP)

MO-153, 4mm Wide

Tube

FST3125MTCX

-40 to 85°C

14-Lead, Thin Shrink Small Outline Package (TSSOP)

MO-153, 4mm Wide

Tape and Reel

All packages are lead free per JEDEC: J-STD-020B standard.

The Fairchild switch family derives from and embodies Fairchild’s proven switch technology used for several years in its

74LVX3L384 (FST3384) bus switch product.

Figure 1. Logic Diagram