The MAX6400–MAX6405 is a family of ultra-low power microprocessor (µP) supervisory circuits used for monitoring battery, power-supply, and regulated system voltages. Each device contains a precision bandgap reference comparator and is trimmed to specified trip threshold voltages. These devices provide excellent circuit reliability and low cost by eliminating external components and adjustments when monitoring system voltages from 2.5V to 5.0V. A manual reset input is also included.The MAX6400–MAX6405 assert a reset signal whenever the VCCsupply voltage falls below a preset threshold. These devices are differentiated by their output logic configurations and preset threshold voltages. The MAX6400/MAX6403 (push-pull) and the MAX6402/MAX6405 (open-drain) have an active-low reset (active-low RESET is logic low when VCCis below VTH). The MAX6401/MAX6404 have an active-high push-pull output (RESET is logic high when VCCis below VTH). All parts are guaranteed to be in the correct output logic state for VCCdown to 1V. The reset circuits designed to ignore fast transients on VCC. The MAX6400/MAX6401/MAX6402 have voltage thresholds between 2.20V and 3.08V in approximately 100mV increments. The MAX6403/MAX6404/MAX6405 have voltage thresholds between 3.30V and 4.63V in approximately 100mV increments.Ultra-low supply current of 500nA (MAX6400/MAX6401/MAX6402) makes these parts ideal for use in portable equipment. These devices are available in 4-bump chip-scale packages (UCSP™)ApplicationsCell PhonesMP3 PlayersPagersPDAsPortable Battery-Powered Equipment