General Description

The MAX4838–MAX4841 are overvoltage protection ICs

that protect low-voltage systems against voltages of up

to 28V. If the input voltage exceeds the overvoltage trip

level, the MAX4838–MAX4841 turn off the low-cost

external N-channel FET(s) to prevent damage to the

protected components. An internal charge pump elimi-

nates the need for external capacitors and drives the

FET gate for a simple, robust solution.

The MAX4838/MAX4839 have a 7.4V overvoltage

threshold, and the MAX4840/MAX4841 have a 5.8V

overvoltage threshold. All devices have an undervolt-

age lockout threshold of 3.25V. In addition to the single

FET configuration, the devices can be configured with

back-to-back external FETs to prevent currents from

being back-driven into the adapter.

On power-up, the device waits for 50ms before driving

GATE high. FLAG is held low for an additional 50ms

after GATE goes high before deasserting. The

MAX4838/MAX4840 have an open-drain FLAG output,

and the MAX4839/MAX4841 have a push-pull FLAG

output. The FLAG output asserts immediately to an

overvoltage fault.

Additional features include a 15kV ESD-protected input

(when bypassed with a 1µF capacitor) and a shutdown

pin (EN) to turn off the device (MAX4838/MAX4840).

All devices are offered in a small 6-pin SC70 package

and are specified for operation from -40°C to +85°C.

Applications

Cell Phones

Digital Still Cameras

PDAs and Palmtop Devices

MP3 Players

Features

o Overvoltage Protection Up to 28V

o Preset 7.4V or 5.8V Overvoltage Trip Level

o Drive Low-Cost NMOS FET

o Internal 50ms Startup Delay

o Internal Charge Pump

o Undervoltage Lockout

o 15kV ESD-Protected Input

o Voltage Fault FLAG Indicator

o 6-Pin SC70 Package

Overvoltage Protection Controllers with

Status FLAG

________________________________________________________________ Maxim Integrated Products

1

MAX4838–

MAX4841

INPUT

+1.2V TO +28V

IN

EN

GATE

FLAG

GND

1

6

4

2

3

OUTPUT

1

µF

NOTE: EN AND PULLUP

RESISTOR ON MAX4838/

MAX4840 ONLY.

NMOS

Typical Operating Circuit

Ordering Information

19-3044; Rev 0; 10/03

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.

Pin Configuration appears at end of data sheet.

PART

TEMP RANGE

PIN-

PACKAGE

TOP

MARK

MAX4838EXT-T

-40°C to +85°C

6 SC70-6

ABW

MAX4839EXT-T

-40°C to +85°C

6 SC70-6

ABY

MAX4840EXT-T

-40°C to +85°C

6 SC70-6

ABX

MAX4841EXT-T

-40°C to +85°C

6 SC70-6

ABZ

Selector Guide

PART

UVLO

THRESHOLD

(V)

OV

TRIP

LEVEL

(V)

EN

INPUT

FLAG

OUTPUT

MAX4838EXT-T

3.25

7.4

Yes

Open-Drain

MAX4839EXT-T

3.25

7.4

No

Push-Pull

MAX4840EXT-T

3.25

5.8

Yes

Open-Drain

MAX4841EXT-T

3.25

5.8

No

Push-Pull