MAX4271 Datasheet, PDF (1/24 Pages) Maxim Integrated Products – 3V to 12V Current-Limiting Hot Swap Controllers with Autoretry, DualSpeed/BiLevel Fault Protection

19-1694; Rev 1a; 4/01
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3V to 12V Current-Limiting Hot Swap Controllers
with Autoretry, DualSpeed/BiLevel Fault Protection
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.
DualSpeed/BiLevel is a trademark of Maxim Integrated
Products.
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
Base Stations
RAID
Remote-Access Servers
Network Routers and
Switches
ISDN
PART
M A X 4 2 7 1ESA
M A X 4 2 7 2ESA
M A X 4 2 7 3EEE
MAX4273ESE
Ordering Information
TEMP. RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
8 SO
8 SO
16 QSOP
16 SO
Pin Configurations appear at end of data sheet.
Typical Operating Circuit
BACKPLANE REMOVABLE CARD
2.7V TO 13.2V
R_SENSE
M1
N
V_CC
STAT
GND
ON
IN
STAT
ON
SENSE
GATE
MAX4271
MAX4272
GND
CSPD
CTIM
V_OUT
C_BOARD
C_TIM
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