Typical Operating Circuit

N

M1

MAX4271

MAX4272

CTIM

CSPD

ON

ON

GND

STAT

STAT

REMOVABLE CARD

2.7V TO 13.2V

BACKPLANE

IN

SENSE

GATE

GND

General Description

The MAX4271/MAX4272/MAX4273 comprise a com-

plete family of integrated 3V to 12V hot-swap con-

trollers. They allow the safe insertion and removal of

circuit cards into live backplanes.

The discharged filter capacitors of the circuit card pro-

vide a low impedance to the live backplane. High in-

rush currents from the backplane to the circuit card can

burn up connectors and components, or momentarily

collapse the backplane power supply leading to a sys-

tem reset. This family of hot-swap controllers prevents

such problems by regulating the current to a preset

limit when the board is plugged in, allowing the system

to stabilize safely. After the startup cycle is completed,

two on-chip comparators provide DualSpeed/BiLevel™

protection against short circuits, load glitches, and

overcurrent conditions. In the event of a fault condition,

the load is disconnected. Fault recovery is handled by

unlatching (MAX4271), autoretry (MAX4272), or pro-

grammed (MAX4273) methods.

The MAX4271 family includes many integrated features

that reduce component count and design time. An on-

board charge pump provides the gate drive for a low-

cost, external N-FET. Integrated features like startup

current regulation and current glitch protection eliminate

external timing resistors and capacitors. Also featured

are an open-drain status output to indicate a fault condi-

tion, and an adjustable overcurrent response time.

The MAX4271 (latched fault protection) and MAX4272

(autoretry fault protection) come in 8-pin SO packages.

The MAX4273 (full function) comes in the space-saving

16-pin QSOP package and 16-pin SO package. All

parts are specified across the extended temperature

range, and have an absolute maximum rating of 15V to

provide extra protection against inductive kickback dur-

ing board removal.

Features

o Provide Safe Hot Swap for +3V to +12V Power

Supplies with Few External Components

o Unique Current Regulation Architecture

Minimizes N-FET Linear Mode Duration

o Autoretry Feature (MAX4272/MAX4273)

o DualSpeed/BiLevel Current Limit Protects Against

Current Glitches and Short Circuits

o Power-On RESET (MAX4273)

o 15V Absolute Maximum Rating Protects Against

Inductive Kickbacks During Board Removal

o Internal Charge Pump Generates Gate Drive for

External N-MOSFET

o Status Output Pin Indicates Fault/Safe Condition

o Space-Saving 8-Pin SO, 16-Pin QSOP Packages

________________________Applications

3V to 12V Current-Limiting Hot Swap Controllers

with Autoretry, DualSpeed/BiLevel Fault Protection

________________________________________________________________ Maxim Integrated Products

1

19-1694; Rev 1a; 4/01

For free samples and the latest literature, visit www.maxim-ic.com or phone 1-800-998-8800.

For small orders, phone 1-800-835-8769.

EVALUATION

KIT

AVAILABLE

DualSpeed/BiLevel is a trademark of Maxim Integrated

Products.

Pin Configurations appear at end of data sheet.

Base Stations

RAID

Remote-Access Servers

Network Routers and

Switches

ISDN

Ordering Information

PART

TEMP. RANGE

PIN-PACKAGE

MAX4271ESA

-40

°C to +85°C

8 SO

MAX4272ESA

-40

°C to +85°C

8 SO

MAX4273EEE

-40

°C to +85°C

16 QSOP

MAX4273ESE

-40

°C to +85°C

16 SO