Datasheet

STM6905 Description
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1 Description
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, networking
and communication systems.
The device supports a push-button type manual reset input (MR
). Two of the five supply
monitors (V
CC
and V2IN) have fixed (customer-selectable, factory-trimmed) thresholds
(V
RST1
and V
RST2
). 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 V
CC
greater than 0.8 V.
The STM6905 is available in a standard 8-lead MSOP (TSSOP) package.
Figure 1. Logic diagram
Figure 2. MSOP/TSSOP-8 connections
V4IN
V
CC
STM6905
MR
RST
V
SS
V5IN
V2IN
V3IN
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1
V3IN
V
SS
V4IN
V5IN
V
CC
MR
RST
V2IN
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2
3
4
8
7
6
5