Detailed Description

The MAX6439–MAX6442 family is available with several

monitoring options. The factory-trimmed thresholds

eliminate the requirement for external components. The

MAX6439/MAX6440 have single low-battery outputs

and the MAX6441/MAX6442 have dual low-battery out-

puts (see Figure 1a and Figure 1b).

The MAX6439–MAX6442 combine a 1.23V reference

with two comparators, logic, and timing circuitry to pro-

vide the user with information about the charge state of

the power-supply batteries. The MAX6441/MAX6442

monitor separate high-voltage and low-voltage thresh-

olds to determine battery status. The output(s) can be

used to signal when the battery is charged, when the

battery is low, and when the battery is empty. Factory-

trimmed thresholds are ideal for monitoring single-cell

Li+ or multicell alkaline/NiCd/NiMH power supplies.

When the power-supply voltage drops below the speci-

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

the voltage rises above the specified high threshold fol-

lowing a 150ms (min) timeout period, the low-battery

output is deasserted. This ensures the supply voltage

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

with Hysteresis and Integrated µP Reset

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7

Pin Description

PIN

MAX6439/

MAX6440

MAX6441/

MAX6442

NAME

FUNCTION

11

Battery Voltage Input. Input for battery voltage threshold monitors and device power supply

23

MR

Manual Reset Input, Active-Low, Internal 1.5k

edge-triggered RESET output for the MR reset timeout period. Leave unconnected or

reset events.

3

—

LBO

least 150ms.

45

RESET

Reset Output, Active Low, Push-Pull or Open Drain. RESET changes from high to low when

pulsed low for the MR reset timeout period when the MR input is pulled low. RESET is an

open-drain output for the MAX6439/MAX6441, and a push-pull output for the

5

2

GND

Ground

68

—

6

LBOH

specification for at least 150ms.

—

7

LBOL

specification for at least 150ms.

—

4

LBOLH

HTH+ specification for at least 150ms.