MAX6366

19-1658; Rev 1; 6/01 SOT23, Low-Power µP Supervisory Circuits with Battery Backup and Chip-Enable Gating General Description The MAX6365–MAX6368 supervisory circuits simplify power-supply monitoring, battery-backup control functions, and memory write protection in microprocessor (µP) systems. The circuits significantly improve the size, accuracy, and reliability of modern systems with an ultrasmall integrated solution. These devices perform four basic system functions: 1) Provide a µP reset output during VCC supply powerup, power-down, and brownout conditions. 2) Internally control VCC to backup-battery switching to maintain data or low-power operation for CMOS RAM, CMOS µPs, real-time clocks, and other digital logic when the main supply fails. 3) Provide memory write protection through internal chip-enable gating during supply or processor faults. 4) Include one of the following options: a manual reset input (MAX6365), a watchdog timer function (MAX6366), a battery-on output (MAX6367), or an auxiliary user-adjustable reset input (MAX6368). The MAX6365–MAX6368 operate from VCC supply voltages as low as 1.2V. The factory preset reset threshold voltages range from 2.32V to 4.63V (see Ordering Information). In addition, each part is offered in three reset output versions: push-pull active low, open-drain active low, or open-drain active high (see Selector Guide). The MAX6365–MAX6368 are available in miniature 8-pin SOT23 packages. Features o Low +1.2V Operating Supply Voltage ...