The IDT logo is a registered trademark of Integrated Device Technology, Inc.

FEATURES:

• Bus switches provide zero delay paths

• Extended commercial range of –40

°C to +85°C

• Low switch on-resistance:

FST3xxx – 5

Ω

• TTL-compatible input and output levels

• ESD > 2000V per MIL-STD-883, Method 3015;

> 200V using machine model (C = 200pF, R = 0)

• Available in QSOP and SOIC

COMMERCIAL TEMPERATURE RANGE

AUGUST 1996

©1996 Integrated Device Technology, Inc.

DSC-4668/-

1

IDT74FST3125

4-BIT BUS SWITCH

capability. Thus they generate little or no noise of their own

while providing a low resistance path for an external driver.

These devices connect input and output ports through an n-

channel FET. When the gate-to-source junction of this FET is

adequately forward-biased the device conducts and the resis-

tance between input and output ports is small.

Without

adequate bias on the gate-to-source junction of the FET, the

has hot insertion capability.

The low on-resistance and simplicity of the connection

between input and output ports reduces the delay in this path

to close to zero.

The FST3125 is a 4-bit TTL-compatible bus switch. The

xOE pins provide individual enable control for each of the four

bits.

DESCRIPTION:

The FST3125 belong to IDT's family of Bus switches. Bus

switch devices perform the function of connecting or isolating

two ports without providing any inherent current sink or source

1A

1Y

2A

2Y

3Y

4Y

3A

4A

4OE

2OE

1OE

3OE

FUNCTIONAL BLOCK DIAGRAM

PIN CONFIGURATION

PIN DESCRIPTION

3471 drw 01

3471 drw 02

3471 tbl 01

Pin Names

I/O

Description

I/O

Bus A

I/O

Bus B

NC

—

No Connect

1

OE, 4OE

I

Bus Switch Enable (Active LOW)

Integrated Device Technology, Inc.

5

6

7

8

1

2

3

4

14

13

12

11

10

9

1A

1Y

NC

2A

2Y

GND

4A

4Y

3A

3Y

NC

Vcc

1OE

SO16-1

SO16-7

15

16

2OE

3OE

4OE

SOIC/QSOP

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