MAXIM MAX696CWE+T

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:

1. A reset output during power-up, power-down, and brownout conditions. The threshold for this “lowline” reset is adjustable by an external voltagedivider.
2. A reset pulse if the optional watchdog timer has not been toggled within a specified time.
3. Individual outputs for low-line and watchdog fault conditions.
4. The reset time may be left at its default value of 50ms, or may be varied with an external capacitor or clock pulses.
5. 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 lowpower logic.

The MAX697 lacks battery-backup switching, but has write-protection pins (CE IN and CE OUT) for CMOS RAM or EPROM. In addition, it consumes less than 250 microamperes.

• 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

• Computers
• Controllers
• Intelligent Instruments
• Critical μP Power Monitoring