Power Supervisors with Battery Backup, Chip-Enable Gating and Power-Fail Warning
Maxim Integrated Products’ MAX16033-MAX16040 low-power, microprocessor supervisory circuits with precision power-supply monitoring and battery control functions are optimized for performance in space-saving 2 mm ×2 mm microDFN packages. These supervisory circuits feature a microprocessor reset, battery backup switchover, power-fail warning, and chip-enable gating, thereby reducing the complexity and number of components for power-supply monitoring. The small size and high integration of the MAX16033-MAX16040 make them appropriate for point-of sale equipment, industrial equipment, fax machines, computers, and set-top boxes. The MAX16033-MAX16040 automatically switch the RAM to the backup battery when Vcc falls below either the reset threshold or Vbatt. These devices also assert a reset when Vcc is below the reset-threshold voltage for at least 150 ms after Vcc returns above its threshold. The MAX16033/MAX16037 feature a manual-reset input, and the MAX16036/MAX16040 feature an auxiliary user-adjustable reset input for monitoring a second voltage. The MAX16034/MAX16038 include a watchdog function that triggers a reset pulse whenever WDI remains high or low for longer than the watchdog timeout period. The MAX16035/MAX16039 feature a battery-on output during battery-backup mode. The MAX16033-MAX16036 provide internal gating of the chip-enable signals to prevent erroneous data from corrupting the CMOS RAM. Each device offers either an active-low, push-pull reset or an active-low, open-drain reset, and includes a power-fail comparator that signals an interrupt when Vpfi falls below 1.235V or when Vcc falls below the reset threshold. Pricing starts at $1.98 (1000-up).
Maxim Integrated Products