STM809, STM810
STM811, STM812
Reset circuit
Features
■
■
Precision monitoring of 3 V, 3.3 V, and 5 V
supply voltages
Two output configurations
– Push-pull RST output (STM809/811)
– Push-pull RST output (STM810/812)
140 ms reset pulse width (min)
Low supply current - 6 µA (typ)
Guaranteed RST/RST assertion down to
V
CC
= 1.0 V
Operating temperature:
–40 °C to 85 °C (industrial grade)
Lead-free, small SOT23 and SOT143 package
SOT143-4 (W1)
SOT23-3 (WX)
■
■
■
■
■
Table 1.
Device summary
Active-low reset
Active-high reset
Manual reset input
Package
SOT23-3
✔
✔
✔
✔
✔
SOT23-3
SOT143-4
SOT143-4
STM809
STM810
STM811
STM812
✔
January 2010
Doc ID 9873 Rev 5
1/21
www.st.com
1
Contents
STM809/810/811/812
Contents
1
2
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.1
2.2
2.3
2.4
Reset output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Push-button reset input (STM811/812) . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Negative-going V
CC
transients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Valid RST output down to V
CC
= 0 V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3
4
5
6
7
8
Typical operating characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
DC and AC parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Part numbering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
2/21
Doc ID 9873 Rev 5
STM809/810/811/812
List of tables
List of tables
Table 1.
Table 2.
Table 3.
Table 4.
Table 5.
Table 6.
Table 7.
Table 8.
Table 9.
Table 10.
Device summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Signal names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Operating and AC measurement conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
DC and AC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
SOT23-3 – 3-lead small outline transistor package mechanical data. . . . . . . . . . . . . . . . . 16
SOT143-4 – 4-lead small outline transistor package mechanical data. . . . . . . . . . . . . . . . 17
Ordering information scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Marking description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Doc ID 9873 Rev 5
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List of figures
STM809/810/811/812
List of figures
Figure 1.
Figure 2.
Figure 3.
Figure 4.
Figure 5.
Figure 6.
Figure 7.
Figure 8.
Figure 9.
Figure 10.
Figure 11.
Figure 12.
Figure 13.
Figure 14.
Figure 15.
Figure 16.
Logic diagram (STM809/810) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Logic diagram (STM811/812) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
SOT23-3 connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
SOT143-4 connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Hardware hookup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Supply current vs. temperature, L/M/R/S/T (no load) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Power-down reset delay vs. temperature - V
OD
= V
TH
– V
CC
(L/M) . . . . . . . . . . . . . . . . . . . 9
Power-down reset delay vs. temperature - V
OD
= V
TH
– V
CC
(R/S/T) . . . . . . . . . . . . . . . . 10
Power-up t
rec
vs. temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Normalized reset threshold vs. temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Max transient duration NOT causing reset pulse vs. reset comparator overdrive . . . . . . . 11
AC testing input/output waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
MR timing waveform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
SOT23-3 – 3-lead small outline transistor package outline . . . . . . . . . . . . . . . . . . . . . . . . 16
SOT143-4 – 4-lead small outline transistor package outline . . . . . . . . . . . . . . . . . . . . . . . 17
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Doc ID 9873 Rev 5
STM809/810/811/812
Description
1
Description
The STM809/810/811/812 microprocessor reset circuits are low-power supervisory devices
used to monitor power supplies. They perform a single function: asserting a reset signal
whenever the V
CC
supply voltage drops below a preset value and keeping it asserted until
V
CC
has risen above the preset threshold for a minimum period of time (t
rec
). The
STM811/812 also provide a push-button reset input (MR).
Figure 1.
Logic diagram (STM809/810)
V
CC
STM809/810
RST (RST)
(1)
V
SS
1. For STM810
AI07832
Figure 2.
Logic diagram (STM811/812)
V
CC
MR
STM811/812
RST (RST)
(1)
V
SS
1. For STM812
AI07831
Table 2.
V
SS
RST
RST
(1)
V
CC
MR
(2)
Signal names
Ground
Active-low reset output
Active-high reset output
Supply voltage
Manual reset input
1. STM810/812 only
2. STM811/812 only
Doc ID 9873 Rev 5
5/21
PCB Design
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