© 2002 Fairchild Semiconductor Corporation

DS500705

www.fairchildsemi.com

May 2002

Revised October 2006

FSTU32X384

20-Bit Low Power Bus Switch

with

−2V Undershoot Protection

General Description

The Fairchild Switch FSTU32X384 provides 20 bits of 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 5-bit switches with separate bus enable (OE) sig-

nals. When OE is LOW, the switch is ON and Port A is con-

nected to Port B. When OE is HIGH, the switch is OPEN

and a high-impedance state exists between the two ports.

The A and B Ports are protected against undershoot to

support an extended range to 2.0V below ground.

Fairchild’s

integrated

Undershoot

Hardened

Circuit

(UHC®) senses undershoot at the I/O and responds by

preventing voltage differentials from developing and turn-

ing the switch on.

Features

s 4

Ω switch connection between two ports

s Minimal propagation delay through the switch

s Ultra low power with

< 0.1 µA typical I

CC

s Zero ground bounce in flow-through mode

s Control inputs compatible with TTL level

s See Application Note AN-5008 for details on

FSTU - Undershoot Protected Fairchild Switch Family

Ordering Code:

Device also available in Tape and Reel. Specify by appending suffix letter “X” to the ordering code.

Logic Diagram

UHC® is a registered trademark of Fairchild Semiconductor Corporation.

Order Number

Package

Number

Package Description

FSTU32X384QSP

MQA48A

48-Lead Quarter Size Very Small Outline Package (QVSOP), JEDEC MO-154, 0.150" Wide