STM6717_07 Datasheet, PDF (5/29 Pages) STMicroelectronics – Dual/triple ultra-low voltage supervisors with push-button reset (with delay option)

STM6717/6718/6719/6720/STM6777/6778/6779/6780
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Description
Description
The STM6717/18/19/20 and STM6777/78/79/80 supervisors are a family of low voltage/low
supply current processor (Micro or DSP) supervisors, designed to monitor two (or three)
system power supply voltages. They are targeted at applications such as Set-Top Boxes
(STBs), portable, battery-powered systems, networking, and communication systems.
All device options have a push-button-type manual reset input (MR). The
STM6777/78/79/80 also includes an option which enables the user to delay the start of the
Manual Reset process from 6µs (MRC pin left open) or more with external capacitor. The
delay is implemented by connecting the appropriately sized capacitor between the MRC pin
and V_SS (typical 4s delay with a 3.3µF capacitor, see Table 7 on page 21).
Two of the three supplies monitored (V_CC1 and V_CC2) have fixed (customer-selectable,
factory-trimmed) thresholds (V_RST1 and V_RST2). The third voltage is monitored using an
externally adjustable RSTIN threshold (0.626V internal reference).
If any of the three monitored voltages drop below its factory-trimmed or adjustable
thresholds, or if MR is asserted to logic low, a RST is asserted (driven low). Once asserted,
RST is maintained at Low for a minimum delay period (t_rec) after ALL supplies rise above
their respective thresholds and MR returns to High. These devices are guaranteed to be in
the correct reset output logic state when V_CC1 and/or V_CC2 is greater than 0.8V.
These devices are available in a standard 5-pin or 6-pin SOT23 packages (see Table 1 on
page 1).
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