Battery backup supervisor in 16-SOIC
The MAX693AEWE is a battery backup circuit from Analog Devices, monitoring a single voltage rail at a 4.4V threshold. The push-pull outputs drive CMOS or TTL logic without external pull-ups.
Threshold and timeout for battery-backed systems
The 4.4V threshold is set for monitoring a 5V rail — typical for microprocessor supply supervision. When the rail falls below this level, the reset outputs assert, holding the processor in reset until the supply stabilises above threshold for the full 140ms timeout period. Having both active-high and active-low outputs gives flexibility: the active-low output connects directly to a microcontroller's /RESET pin, while the active-high output can drive an enable line or power-up sequencing logic. The push-pull topology means no external resistor is needed on either output. The 16-SOIC wide-body package provides a larger thermal pad area than the narrow SOIC, aiding heat dissipation in the supervisor's own linear regulator stage.