The STM6905 supervisor is a low voltage/low supply current processor supervisor, designed to monitor up to five system power supply voltages. This device is targeted at applications such as set-top boxes (STBs), portable, battery-powered systems, and networking and communication systems.
The device supports a push-button type manual reset input (MR). Two of the five supply monitors (VCC and V2IN) have fixed (customer-selectable, factory-trimmed) thresholds (VRST1 and VRST2). The other three voltage monitor inputs (V3IN, V4IN and V5IN) are monitored using externally adjustable threshold (600 mV internal reference) to meet specific level requirements.
If any of the five monitored voltages drops below its factory-trimmed or adjustable thresholds, or if the MR is asserted to logic low, the reset output RST is asserted (driven low). Once asserted, RST is maintained Low for a minimum delay period (trec) after ALL monitored supplies rise above their respective thresholds and MR returns to High. Reset output logic state is valid for VCC greater than 0.8 V.