Low-Power, Adjustable Battery Monitors with Hysteresis and Integrated µP Reset

Active: In Production.

The MAX6846–MAX6849 are a family of ultra-low-power battery monitors with integrated microprocessor (µP) supervisors. The user-adjustable battery monitors are offered with single or dual low-battery output options that can be used to signal when the battery is OK (enabling full system operation), when the battery is low (for low-power system operation), and when the battery is dead (to disable system operation). These devices also have an independent µP supervisor that monitors V_CC and provides an active-low reset output. A manual reset function is available to reset the µP with a pushbutton.

The MAX6846–MAX6849 are ideal for single-cell lithium-ion (Li+) or multicell alkaline/NiCd/NiMH applications. When the battery voltage drops below each adjusted low threshold, the low-battery outputs are asserted to alert the system. When the voltage rises above the adjusted high thresholds, the outputs are deasserted after a 150ms minimum timeout period, ensuring the voltages have stabilized before power circuitry is activated or providing microprocessor reset timing.

These devices have user-adjustable battery threshold voltages, providing a wide hysteresis range to prevent chattering that can result due to battery recovery after load removal. Single low-battery outputs are supplied by the MAX6846/MAX6847 and dual low-battery outputs are supplied by the MAX6848/MAX6849. All battery monitors have open-drain low-battery outputs.

The MAX6846–MAX6849 monitor system voltages (V_CC) from 1.8V to 3.3V with seven fixed reset threshold options. Each device is offered with two minimum reset timeout periods of 150ms or 1200ms. The MAX6846/MAX6848 are offered with an open-drain active-low RESET output and the MAX6847/MAX6849 are offered with a push-pull active-low RESET output.

The MAX6846–MAX6849 are offered in a SOT23 package and are fully specified over a -40°C to +85°C temperature range.

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