
General Description
The MAX5927/MAX5929 +1V to +13.2V quad hot-swap
controllers provide complete protection for multisupply
systems. They allow the safe insertion and removal of cir-
cuit cards into live backplanes. These devices hot swap
multiple supplies ranging from +1V to +13.2V, provided
one supply is at or above +2.7V and only one supply is
above +11.0V. The input voltage rails (channels) can be
configured to sequentially turn-on/off, track each other,
or have completely independent operation.
The discharged filter capacitors of the circuit card pro-
vide low impedance to the live backplane. High inrush
currents from the backplane to the circuit card can burn
up connectors and components, or momentarily collapse
the backplane power supply leading to a system reset.
The MAX5927/MAX5929 hot-swap controllers prevent
such problems by gradually ramping up the output volt-
age and regulating the current to a preset limit when the
board is plugged in, allowing the system to stabilize
safely. After the startup cycle is complete, on-chip com-
parators provide VariableSpeed/BiLevel protection
against short-circuit and overcurrent faults, and provide
immunity against system noise and load transients. The
load is disconnected in the event of a fault condition. The
MAX5929A automatically restarts after a fault condition,
while the MAX5929L must be unlatched. The MAX5927
fault management mode is selectable.
The MAX5927/MAX5929 offer a variety of options to
reduce external component count and design time. All
devices integrate an on-board charge pump to drive
the gates of low-cost external N-channel MOSFETs, an
adjustable startup timer, and an adjustable current limit.
The devices offer integrated features like startup cur-
rent regulation and current glitch protection to eliminate
external timing resistors and capacitors. The
MAX5929_L provides an open-drain active-low status
output for each channel, the MAX5929_H provides an
open-drain active-high status output for each channel,
and the MAX5927 status output polarity is selectable.
The MAX5927 is available in a 32-pin thin QFN package
and the MAX5929 is available in a 24-pin QSOP pack-
age. All devices are specified over the extended tem-
perature range, -40°C to +85°C.
Applications
Features
Safe Hot Swap for +1V to +13.2V Power Supplies
with Any Input Voltage (V
IN_
≥
2.7V and Only One
V
IN_
> 11.0V)
Adjustable Circuit Breaker/Current-Limit
Threshold from 25mV to 100mV
Configurable Tracking, Sequencing, or
Independent Operation Modes
VariableSpeed/BiLevel Circuit-Breaker Response
Internal Charge Pumps Generate N-Channel
MOSFET Gate Drives
Inrush Current Regulated at Startup
Autoretry or Latched Fault Management
Programmable Undervoltage Lockout
Status Outputs Indicate Fault/Safe Condition
M
Low-Voltage, Quad, Hot-Swap
Controllers/Power Sequencers
________________________________________________________________
Maxim Integrated Products
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
1
3
3
3
2
2
2
2
L
O
O
P
M
O
O
2
L
9
1
1
1
1
1
1
S
T
N
L
S
S
B
1
G
17
18
19
20
21
22
23
GATE3
SENSE3
IN3
N.C.
LIM3
GATE2
SENSE2
8
7
6
5
4
3
2
STAT1
GATE4
SENSE4
IN4
LIM4
GATE1
SENSE1
MAX5927
THIN QFN
1
IN1
24
IN2
TOP VIEW
Pin Configurations
Ordering Information
19-2945; Rev 1; 1/04
EVALUATION KIT
AVAILABLE
PART
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
32 Thin QFN-EP
24 QSOP
24 QSOP
24 QSOP
24 QSOP
MAX5927
ETJ
MAX5929
LHEEG
MAX5929LLEEG
MAX5929AHEEG
MAX5929ALEEG
EP = Exposed paddle.
VariableSpeed/BiLevel is a trademark of Maxim Integrated
Products, Inc.
PCI Express Hot Plug
Hot Plug-In Daughter Cards
RAID
Power-Supply
Sequencing/Tracking
Basestation Line Cards
Portable Computer Device
Bays (Docking Stations)
Network Switches, Routers,
Hubs
Selector Guide and Typical Operating Circuit appear at end
of data sheet.
Pin Configurations continued at end of data sheet.