The MAX6427-MAX6438 are single/dual-level battery monitors 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 output 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 microprocessor 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 single 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 output 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.
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)
Low Current (1µA, typ)
Single or Dual Low-Battery Outputs
Push-Pull active-low LBO, Open-Drain active-low LBO, and Open-Drain LBO Options