MAX6428

19-2323; Rev 1; 9/03 Low-Power, Single/Dual-Level Battery Monitors with Hysteresis General Description 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 lowbattery 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 lowbattery outputs. The MAX6433–MAX6438 have user-adjustable threshold voltages permitting the user to select the hysteresis range, and consequently the sensitivity of the syst...