For additional information, contact Don Ashley at

Donald.Ashley@nsc.com

General Description

The LM5068 hot-swap controller provides intelligent con-

trol of power supply connections during the insertion and

removal of circuit cards powered by live system backplanes

The LM5068 provides both in-rush current control and

short-circuit protection functions, and limits power supply

transients in the backplane caused by the insertion of

additional circuit cards. The LM5068 controls the external

N-Channel MOSFET to provide programmable load current

limiting and circuit breaker functions using a single external

current sense resistor. The LM5068 issues a power good

(PWRGD) signal at the conclusion of a successful power-

on sequence.

Input over-voltage or under-voltage fault

conditions will cancel the PWRGD indication.

The LM5068-1 and -2 indicate power good as an open-

drain active high PWRGD state.

The LM5068-3 and -4

indicate power-good as an open-drain active low PWRGD

state. The LM5068-1 and -3 latch off after a fault condition

is detected while the LM5068-2 and -4 continuously re-try

at intervals set by a programmable timer.

The LM5068 is available in MSOP-8 package.

LM5068

Negative Voltage Hot-Swap Controller

Features

live backplanes

active current limiting

shutdown protection with adjustable hysteresis

insertion de-bounce delay

duration load transients

versions

power good flag

© 2003 National Semiconductor Corporation

PRELI

MINARY

Samples are available now; volume production is expected

in late January 2004.