TLF5225

March 1995

DS3668 Quad Fault Protected Peripheral Driver

General Description

The DS3668 quad peripheral driver is designed for those

applications where low operating power high breakdown

voltage high output current and low output ON voltage are

required Unlike most peripheral drivers available a unique

fault protection circuit is incorporated on each output When

the load current exceeds 10A (approximately) on any out-

put for more than a built-in delay time nominally 12 ms that

output will be shut off by its protection circuitry with no effect

on other outputs This condition will prevail until that protec-

tion circuitry is reset by toggling the corresponding input or

the enable pin low for at least 10 ms This built-in delay is

provided to ensure that the protection circuitry is not trig-

gered by turn-on surge currents associated with certain

kinds of loads

The DS3668’s inputs combine TTL compatibility with high

input impedance In fact its extreme low input current al-

lows it to be driven directly by a MOS device The outputs

are capable of sinking 600 mA each and offer a 70V break-

down However for inductive loads the output should be

clamped to 35V or less to avoid latch up during turn off

(inductive fly-back protection

refer AN-213) An on-chip

clamp diode capable of handling 800 mA is provided at

each output for this purpose In addition the DS3668 incor-

porates circuitry that guarantees glitch-free power up or

down operation and a fail-safe feature which puts the output

in a high impedance state when the input is open

The molded package is specifically constructed to allow in-

creased power dissipation over conventional packages The

four ground pins are directly connected to the device chip

with a special copper lead frame When the quad driver is

soldered into a PC board the power rating of the device

improves significantly

Applications

Y

Relay drivers

Y

Solenoid drivers

Y

Hammer drivers

Y

Stepping motor drivers

Y

Triac drivers

Y

LED drivers

Y

High current high voltage drivers

Y

Level translators

Y

Fiber optic LED drivers

Features

Y

Output fault protection

Y

High impedance TTL compatible inputs

Y

High output current600 mA per output

Y

No output latch-up at 35V

Y

Low output ON voltage (550 mV typ

600 mA)

Y

High breakdown voltage (70V)

Y

Open collector outputs

Y

Output clamp diodes for inductive fly-back protection

Y

NPN inputs for minimal input currents (1 mA typical)

Y

Low operating power

Y

Standard 5V power supply

Y

Power updown protection

Y

Fail-safe operation

Y

2W power package

Y

Pin-for-pin compatible with SN75437

Connection Diagram

Dual-In-Line Package

TLF5225 – 1

Top View

Truth Table

IN

EN

OUT

HH

L

LH

Z

HL

Z

LL

Z

Order Number DS3668N

See NS Package Number N16E

C1995 National Semiconductor Corporation

RRD-B30M105Printed in U S A