High Voltage Input Protection Device

Data Sheet

ADM1270

Rev. A

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FEATURES

Controls supply voltages from 4 V to 60 V

Gate drive for low voltage drop reverse supply protection

Gate drive for P-channel FETs

Inrush current limiting control

Adjustable current limit

Foldback current limiting

Automatic retry or latch-off on current fault

Programmable current-limit timer for safe operating area (SOA)

Power-good and fault outputs

Analog undervoltage (UV) and overvoltage (OV) protection

16-lead, 3 mm × 3 mm LFCSP

16-lead QSOP

APPLICATIONS

Industrial modules

Battery-powered/portable instrumentation

GENERAL DESCRIPTION

The ADM1270 is a current-limiting controller that provides

inrush current limiting and overcurrent protection for modular

or battery-powered systems. When circuit boards are inserted

into a live backplane, discharged supply bypass capacitors draw

large transient currents from the backplane power bus as they

charge. These transient currents can cause permanent damage

to connector pins, as well as dips on the backplane supply that

can reset other boards in the system.

The ADM1270 is designed to control the inrush current, when

powering on the system, via an external P-channel field effect

transistor (FET).

To protect the system from a reverse polarity input supply, there

is a provision made to control an additional external P-channel

FET. This feature prevents reverse current flow in case of a reverse

polarity connection, which can damage the load or the ADM1270.

The ADM1270 is available in a 3 mm × 3 mm, 16-lead LFCSP and

a 16-lead QSOP.

SIMPLIFIED FUNCTIONAL BLOCK DIAGRAM

1V

1V

GATE DRIVE/

LOGIC

TIMER

ON

TIMEOUT

CURRENT

LIMIT

TIMER

VCC/SENSE+ SENSE–

GATE

TIMER

GND

UV

OV

RPFG

FLB

LDO

VCAP

REF

SELECT

ISET

FAULT

FB_PG

ENABLE

TIMER_OFF

PWRGD

+

+

+

–

–

+

–

–

CURRENT-

LIMIT

CONTROL

ADM1270

Figure 1.