© 1999 Fairchild Semiconductor Corporation

DS500022

www.fairchildsemi.com

June 1997

Revised December 1999

FST6800

10-Bit Bus Switch with Pre-Charged Outputs

General Description

The Fairchild Switch FST6800 provides 10-bits of high-

speed CMOS TTL-compatible bus switching. 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 precharges

the B Port to a selectable bias voltage (BiasV) to minimize

live insertion noise.

The device is organized as a 10-bit switch with a bus

enable (OE) signal. 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 the B Port is precharged to BiasV

through an equivalent 10-k

Ω resistor.

Features

s 4

Ω switch connection between two ports.

s Minimal propagation delay through the switch.

s Zero bounce in flow-through mode.

s Output precharge to minimize live insertion noise.

s Control inputs compatible with TTL level.

Ordering Code:

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

Logic Diagram

Pin Descriptions

Connection Diagram

Truth Table

Order Number

Package Number

Package Description

FST6800WM

M24B

24-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300 Wide

FST6800QSC

MQA24

24-Lead Quarter Size Outline Package (QSOP), JEDEC MO-137, 0.150 Wide

FST6800MTC

MTC24

24-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mm Wide

Pin Name

Description

OE

Bus Switch Enable

ABus A

BBus B

OE

Function

Connect

HBiasV

Precharge