2.7 V to 16.5 V Hot Swap Controller

with Power-Fail Comparator

ADM1172

Rev. 0

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FEATURES

GENERAL DESCRIPTION

Controls supply rails from 2.7 V to 16.5 V

The ADM1172 is a hot swap controller that safely enables a

printed circuit board to be removed and inserted to a live

backplane. This is achieved using an external N-channel power

MOSFET with a current control loop that monitors the load

current through a sense resistor. An internal charge pump is

used to enhance the gate of the N-channel FET. When an over-

current condition is detected, the gate voltage of the FET is

reduced to limit the current flowing through the sense resistor.

During an overcurrent condition, the TIMER pin capacitor

determines the amount of time the FET remains at a current

limiting mode of operation until it is shut down. The ON

(ON-

Allows protected board removal and insertion to a live

backplane

External sense resistor provides adjustable analog current

limit with circuit breaker

Peak fault current limited with fast response

Charge pumped gate drive for external N-FET switch

Power-fail comparator

Automatic retry or latch-off during current fault

Undervoltage lockout

8-lead, TSOT package

CLR) pin is the enable input for the device and can be

used to monitor the input supply voltage. The ADM1172

operates with a supply voltage ranging from 2.7 V to 16.5 V.

APPLICATIONS

Hot swap board insertion: line cards, raid systems

Industrial high-side switches/circuit breakers

The ADM1172 also features a power-fail comparator. The

voltage on the PFI pin is compared with an internal 0.6 V

reference, and the output of this comparator is presented on

the PFO pin. This device is available in two options: the

ADM1172-1 with automatic retry for overcurrent fault and the

ADM1172-2 with latch-off for an overcurrent fault. Toggling

the ON (ON-

Electronic circuit breakers

CLR) pin resets a latched fault. The ADM1172 is

packaged in an 8-lead TSOT.

FUNCTIONAL BLOCK DIAGRAM

LONG

LONG

SHORT

SENSE

GATE

ON

TIMER

PFI

PFO

ADM1172-1

GND

GND

GND

Figure 1.