_______________________________________________________________ Maxim Integrated Products 1

For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,

or visit Maxim’s website at www.maxim-ic.com.

1V to 16V, Single-Channel, Hot-Swap Controllers

with Precision Current-Sensing Output

General Description

The MAX5977A/MAX5977B hot-swap controllers provide

complete protection for systems with a 1V to 16V single-

supply voltage.

During the initial insertion, the hot-swap controllers

limit the inrush current from damaging the board or

from shorting out the backplane. When the input volt-

age is above the undervoltage threshold and below the

overvoltage threshold, a 5FA current source powered

from the internal 5V charge pump drives the gate of an

external n-channel MOSFET, providing a slow turn-on

response. An internal current-sense amplifier in the IC

monitors the current across an external shunt resistor,

providing current sensing for wide input-sense voltage

range. The devices provide two levels of overcurrent

circuit-breaker protections: a fast-trip threshold for a fast

turn-off and a lower slow-trip threshold for a delayed

turn-off.

Exceeding either of the overcurrent circuit-breaker

thresholds forces the device into fault mode where the

external n-channel MOSFET is disabled. The MAX5977

is available in two versions that provide a latched-off

(MAX5977A) or autoretry (MAX5977B) output when the

device is in fault mode.

A calibration mode allows further calibration of the inte-

grated transconductance amplifier for production testing

of the final design. The devices are offered in a 20-pin,

4mm x 4mm, TQFN-EP package and are fully specified

from -40NC to +85NC.

Features

S

1% Accurate Current-Sense Amplifier Output

S

Hot-Swap Monitors Operation from 1V to 16V

S

Integrated Charge Pump Fully Enhances the

S

VariableSpeed/BiLevelK Fault Protection Provides

Electronic Circuit-Breaker Function

S

Output Latched Off After Fault Condition

(MAX5977A)

S

Autoretry After Fault Condition (MAX5977B)

S

Power-Good Indicator

S

Calibration Mode

S

Small, 20-Pin, 4mm x 4mm TQFN-EP Package

Applications

Servers

Storage Systems

Network Switches and Routers

General Hot-Swap

19-5553; Rev 2; 7/11

Ordering Information

Typical Operating Circuit

VariableSpeed/BiLevel is a trademark of Maxim Integrated

Products, Inc.

Note: All devices are specified over the -40NC to +85NC oper-

ating temperature range.

+Denotes a lead(Pb)-free/RoHS-compliant package.

*EP = Exposed pad.

EVALUATION

KIT

AVAILABLE

MAX5977A

MAX5977B

CALSENSE

SOURCE

CSOUT

FAULT

PG

CAL

PWR

AGND

SCOMP

FCOMP

IN

SENSE

GATE

GND

2.7V TO 16V

CALIBRATION

MODE INPUT

+3.3V

TO LOAD

CURRENT-SENSE

AMPLIFIER OUTPUT

FAULT OUTPUT

POWER-GOOD OUTPUT

1V TO 16V

PART

PIN-PACKAGE

FAULT RESPONSE

MAX5977AETP+

20 TQFN-EP*

Latched

MAX5977BETP+

20 TQFN-EP*

Autoretry