General Description

The MAX6427–MAX6438 are single/dual-level battery mon-

itors with internal hysteresis. These devices are offered with

single (MAX6427/MAX6428/MAX6429, MAX6433/

MAX6434/MAX6435) or dual (MAX6430/MAX6431/

MAX6432, MAX6436/MAX6437/MAX6438) low-battery out-

put indicators, which can be used to indicate three battery

conditions: battery is good (operate system in normal

mode), battery is weak (operate system in low-power

mode), or battery is empty (disable the system).

These devices are ideal for monitoring single lithium-ion

(Li+) cells or multicell alkaline/NiCd/NiMH power supplies.

When the power-supply voltage drops below the specified

low threshold, the low-battery output asserts. When the

voltage rises above the specified high threshold, the low-

battery output is deasserted following a 140ms minimum

timeout period. The timeout period ensures that the supply

voltages have stabilized before power-converter or micro-

processor activity is enabled.

The MAX6427–MAX6438 family is available with several

monitoring options. The MAX6427/MAX6428/MAX6429

offer factory-trimmed battery-monitor thresholds, with a sin-

gle low-battery output. The MAX6430/MAX6431/MAX6432

also feature factory-trimmed thresholds, but have two low-

battery outputs.

The MAX6433–MAX6438 have user-adjustable threshold

voltages permitting the user to select the hysteresis range,

and consequently the sensitivity of the system to noise. A

wide hysteresis range also prevents chattering that can

result due to battery recovery after load removal. Single

low-battery outputs are supplied by the MAX6433/

MAX6434/MAX6435 and dual low-battery outputs by the

MAX6436/MAX6437/MAX6438.

The MAX6427–MAX6438 family is available with three out-

put logic options for convenient interface with system

power circuitry or microprocessors. The family is offered in

small SOT23 and SOT143 packages and is fully specified

over temperature.

________________________Applications

Battery-Powered Systems (Single-Cell Li+ or

Two/Three-Cell NiMH, NiCd, Alkaline)

Cell Phones/Cordless Phones

Pagers

Portable Medical Devices

PDAs

Electronic Toys

MP3 Players

Features

o Factory-Trimmed or User-Adjustable Threshold

Options

Factory-Trimmed Low Thresholds from 1.6V to

2.1V or 2.6V to 3.1V in 100mV Increments

(MAX6427–MAX6432)

Factory-Trimmed High Thresholds from 2.3V to

2.6V or 3.3V to 3.6V in 100mV Increments

(MAX6427–MAX6432)

User-Adjustable Low/High Thresholds with

615mV Internal Reference (MAX6433–MAX6438)

o Low Current (1µA, typ)

o Single or Dual Low-Battery Outputs

o Push-Pull LBO, Open-Drain LBO, and Open-Drain

LBO Options

o 140ms Minimum LBO Timeout Period

o Immune to Short Battery Voltage Transients

o Guaranteed Valid LBO Logic State to BATT = 1.0V

o -40°C to +85°C Operating Temperature Range

o Small 3, 4, 5 and 6-Pin SOT Packages

o No External Components Required

(MAX6427–MAX6432)

Low-Power, Single/Dual-Level Battery Monitors

with Hysteresis

________________________________________________________________ Maxim Integrated Products

1

19-2323; Rev 1; 9/03

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.

Ordering Information

Typical Operating Circuit appears at end of data sheet.

PART

TEMP RANGE

PIN-PACKAGE

MAX6427_ _UR-T

-40°C to +85°C

3 SOT23-3

Ordering Information continued at end of data sheet.

Pin Configurations continued at end of data sheet.

battery-monitor thresholds. Select the desired thresholds

using Tables 1 or 2 and enter the corresponding letters in

the part number by replacing “_ _”.

Note: There are 26 standard versions with a required order

minimum of 2500 pieces. Sample stock is generally held on

the standard versions only (see Standard Versions Table).

Required order increment is 10,000 pieces for nonstandard

versions. Contact factory for availability. All devices avail-

able in tape-and-reel only.

BATT

1

3

GND

( ) ARE FOR THE MAX6429.

MAX6427

MAX6428

MAX6429

SOT23-3

TOP VIEW

2

LBO

(LBO)

Pin Configurations