© 2005 Fairchild Semiconductor Corporation

DS500448

www.fairchildsemi.com

June 2001

Revised January 2005

FSTD3125

4-Bit Bus Switch with Level Shifting

General Description

The Fairchild Switch FSTD3125 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

integrated into the circuit to allow for level shifting between

5V inputs and 3.3V outputs.

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 4

Ω switch connection between two ports

s Minimal propagation delay through the switch

s Zero bounce in flow-through mode

s Control inputs compatible with TTL level

s TruTranslation

 voltage translation from 5.0V inputs to

3.3V outputs

Ordering Code:

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

Pb-Free package per JEDEC J-STD-020B.

Connection Diagrams

Pin Assignment for SOIC and TSSOP

Pin Assignment for QSOP

Pin Descriptions

Truth Table

TruTranslation

 is a trademark of Fairchild Semiconductor Corporation.

Order

Package

Package Description

Number

Number

FSTD3125M

M14A

14-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150" Narrow

FSTD3125QSC

MQA16

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

FSTD3125MTC

MTC14

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

FSTD3125MTC_NL

MTC14

Pb-Free 14-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mm Wide

Pin Name

Description

Bus Switch Enables

1A, 2A, 3A, 4A

Bus A

1B, 2B, 3B, 4B

Bus B

NC

Not Connected

Inputs

Inputs/Outputs

OE

A, B

LA

= B

HZ