MAX6427 View Datasheet(PDF) - Maxim Integrated

Part Name

Description

Manufacturer

MAX6427

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

Maxim Integrated 

Low-Power, Single/Dual-Level Battery Monitors

with Hysteresis

VBATT

VBATT

615

mV

+

-

HYSTERESIS SWITCH

LBO

TIMEOUT

PERIOD

LBOL

(LBOL)

LBOH

(LBOH)

HYSTERESIS SWITCH

( ) ARE FOR THE MAX6432

Figure 2. MAX6430/MAX6431/MAX6432 Functional Diagram

device to monitor and operate from direct battery voltage

while interfacing to higher voltage microprocessors.

The MAX6427/MAX6428/MAX6429/MAX6433/MAX6434/

MAX6435 single-output voltage monitors provide a sin-

gle low-battery output, LBO/LBO. The MAX6427/

MAX6428/MAX6429 fixed-threshold parts assert

LBO/LBO when BATT drops below VLTH. The

MAX6433/MAX6434/MAX6435 adjustable-threshold

parts assert LBO/LBO when the LTHIN input drops

below the VLTHIN threshold (615mV) (see Figure 5).

The MAX6430/MAX6431/MAX6432/MAX6436/MAX6437/

MAX6438 dual-output voltage monitors provide two low-

battery outputs, LBOH/LBOH and LBOL/LBOL. The

MAX6430/MAX6431/MAX6432 fixed-threshold parts

assert LBOH/LBOH when BATT drops below VHTH-,

and assert LBOL/LBOL when BATT drops below VLTH-.

The MAX6436/MAX6437/MAX6438 adjustable-thresh-

old parts assert LBOH/LBOH when HTHIN drops below

VHTHIN-, and assert LBOL/LBOL when LTHIN drops

below VLTHIN- (see Figure 6).

Threshold Monitoring

The MAX6433–MAX6438 HTHIN and LTHIN inputs are

high-impedance inputs to comparators. An external resis-

tor-divider network is required between the monitored

voltage, HTHIN, LTHIN, and GND to select the desired

thresholds (see Resistor-Value Selection). The

MAX6433/MAX6434/MAX6435 single-output voltage

monitors assert LBO/LBO when LTHIN drops below the

internal LTHIN reference (615mV). LBO/LBO is deassert-

ed when HTHIN rises above the internal HTHIN reference

level (615mV) for at least 140ms (see Figure 6).

The MAX6436/MAX6437/MAX6438 dual-output voltage

monitors assert LBOL/LBOL when LTHIN drops below

the LTHIN- threshold and deassert LBOL/LBOL when

LTHIN rises above the LTHIN+ threshold for at least

140ms. LBOH/LBOH is asserted when HTHIN drops

below the HTHIN- threshold and is deasserted when

HTHIN rises above the HTHIN+ threshold for at least

140ms (see Figure 7).

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