DC-to-DC Converter Application

The MAX6441/MAX6442 triple-output battery monitors

can be used in conjunction with a DC-to-DC converter

to power microprocessor systems using a single Li+

cell or two to three alkaline/NiCd/NiMH cells. The LBOH

output indicates that the battery voltage is weak, and is

used to warn the microprocessor of potential problems.

Armed with this information, the microprocessor can

reduce system power consumption. The LBOL output

indicates the battery is empty, and system power

should be disabled. By connecting LBOL to the SHDN

pin of the DC-to-DC converter, power to the microproces-

sor is removed. Microprocessor power does not return

until the battery has recharged to a voltage greater than

Low-Power, Single-/Dual-Level Battery Monitors

with Hysteresis and Integrated µP Reset

______________________________________________________________________________________

11

UPPER THRESHOLD (HTH)

VOLTAGES

3.3V

3.4V

3.5V

3.6V

2.6V

AG

AH

AI

AJ

2.7V

BG

BH

BI

BJ

2.8V

CG

CH

CI

CJ

2.9V

DG

DH

DI

DJ

3.0V

EG

EH

EI

EJ

LOWER

THRESHOLD

(LTH)

3.1V

FG

FH

FI

FJ

Table 1. Factory-Trimmed Lower and Upper Threshold Combinations for Single-Cell Li+

or Three-Cell Alkaline/NiCd/NiMH Applications

UPPER THRESHOLD (HTH)

VOLTAGES

2.3V

2.4V

2.5V

2.6V

1.6V

KQ

KR

KS

KT

1.7V

LQ

LR

LS

LT

1.8V

MQ

MR

MS

MT

1.9V

NQ

NR

NS

NT

2.0V

OQ

OR

OS

OT

LOWER

THRESHOLD

(LTH)

2.1V

PQ

PR

PS

PT

Table 2. Factory-Trimmed Lower and Upper Threshold Combinations for Two-Cell

Alkaline/NiCd/NiMH Applications

PART NO.

SUFFIX

( _ )

RESET

THRESHOLD (V)

T

3.075

S

2.925

R

2.625

Z

2.313

Y

2.188

W

1.665

V

1.575

Threshold Levels

ACTIVE TIMEOUT PERIOD (ms)

TIMEOUT

PERIOD SUFFIX

MIN

MAX

D3

150

300

D7

1200

2400

Guide