STM6904/STM6905 Current Processor Supervisors

STMicroelectronics' 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 (V_CC and V_2IN) have fixed (customer-selectable, factory-trimmed) thresholds (V_RST1 and V_RST2). The other three voltage monitor inputs (V_3IN, V_4IN, and V_5IN) 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 (T_REC) after all monitored supplies rise above their respective thresholds and MR returns to high. Reset output logic state is valid for V_CC greater than 0.8 V.