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MAX697：Microprocessor Supervisory Circuits

Industry-Standard, Full-Function uP Supervisor

The MAX696/MAX697 supervisory circuits reduce the complexity and number of components required for power-supply monitoring and battery-control functions in microprocessor (µP) systems. These include µP reset and backup-battery switchover, watchdog timer, CMOS RAM write protection, and power-failure warning. The MAX696/MAX697 significantly improve system reliability and accuracy compared to that obtained with separate ICs or discrete components. The MAX696 and MAX697 are supplied in 16-pin packages and perform six functions: A reset output during power-up, power-down, and brownout conditions. The threshold for this "lowline" reset is adjustable by an external voltage-divider. A reset pulse if the optional watchdog timer has not been toggled within a specified time. Individual outputs for low-line and watchdog fault conditions. The reset time may be left at its default value of 50ms, or may be varied with an external capacitor or clock pulses. A separate 1.3V threshold detector for power-fail warning, low-battery detection, or to monitor a power supply other than VCC. The MAX696 also has battery-backup switching for CMOS RAM, CMOS microprocessor, or other low-power logic. The MAX697 lacks battery-backup switching, but has write-protection pins (active-low CE IN and active-low CE OUT) for CMOS RAM or EPROM. In addition, it consumes less than 250 microamperes.

Key Features Adjustable Low-Line Monitor and Power-Down Reset Power-OK/Reset Time Delay Watchdog Timer—100ms, 1.6s, or Adjustable Minimum Component Count 1µA Standby Current Battery-Backup Power Switching (MAX696) On-Board Gating of Chip-Enable Signals (MAX697) Separate Monitor for Power-Fail or Low-Battery Warning

MAX696, MAX697: Block Diagram Applications/Uses Computers Controllers Critical µP Power Monitoring Intelligent Instruments

DataSheet

Parametrics

Quality and Environmental Data

• MAX697.pdf

Ordering Information