Datasheet

Table Of Contents
STM6717/6718/6719/6720/STM6777/6778/6779/6780 Description
Doc ID 11469 Rev 8 5/30
1 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 6 µs (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 4 s delay with a 3.3 µF 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 (0.626 V 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 0.8 V.
These devices are available in standard 5-pin or 6-pin SOT23 packages (see Ta bl e 1 o n
page 1).