STM6321/6322
STM6821/6822/6823/6824/6825
5-pin supervisor with watchdog timer and push-button reset
Features
■
■
■
■
■
■
■
■
■
■
Precision V
CC
monitoring of 5, 3.3, 3, or 2.5 V
power supplies
RST outputs (active-low, push-pull or open
drain)
RST outputs (active-high, push-pull)
Reset pulse width of 1.4 ms, 200 ms and
240 ms (typ)
(a)
Watchdog timeout period of 1.6 s (typ)
(a)
Manual reset input (MR)
Low supply current - 3 µA (typ)
Guaranteed RST (RST) assertion down to
V
CC
= 1.0 V
Operating temperature: –40 to +85°C
(industrial grade)
RoHS compliance
Lead-free components are compliant with the
RoHS directive
Other t
rec
and watchdog timings are
offered. Minimum order quantities may
apply. Contact local sales office for
availability.
Device summary
Reset output
Part number
Watchdog input
Manual reset
input
Active-low
(push-pull)
Active-high
(push-pull)
✔
✔
✔
✔
✔
✔
✔
✔
✔
✔
✔
✔
✔
✔
✔
✔
✔
✔
Active-low
(open drain)
✔
✔
SOT23-5 (WY)
a.
Table 1.
STM6321
STM6322
STM6821
STM6822
STM6823
STM6824
STM6825
✔
June 2008
Rev 8
1/28
www.st.com
1
Contents
STM6321/6322STM6821/6822/6823/6824/6825
Contents
1
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.1
Pin descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.1.1
1.1.2
1.1.3
1.1.4
1.1.5
Active-low, push-pull reset output (RST) - STM6822/6823/6824/6825 . . 7
Active-low, open drain reset output (RST) - STM6321/6322/6822 . . . . . 7
Push-button reset input (MR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Watchdog input (WDI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Active-high reset output (RST) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.1
2.2
2.3
2.4
2.5
Reset output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Open drain RST output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Push-button reset input (STM6322/6821/6822/6823/6825) . . . . . . . . . . . 11
Watchdog input (STM6321/6821/6822/6823/6824) . . . . . . . . . . . . . . . . . 11
Applications information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.5.1
2.5.2
Watchdog input current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Ensuring a valid reset output down to V
CC
= 0 V . . . . . . . . . . . . . . . . . . 11
2.6
Interfacing to microprocessors with bidirectional reset pins . . . . . . . . . . . 12
3
4
5
6
7
8
Typical operating characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
DC and AC parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Part numbering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
2/28
STM6321/6322STM6821/6822/6823/6824/6825
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
Pin functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Operating and AC measurement conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
DC and AC characteristic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
SOT23-5 – 5-lead small outline transistor package mechanical data. . . . . . . . . . . . . . . . . 24
Ordering information scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Marking description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
3/28
List of figures
STM6321/6322STM6821/6822/6823/6824/6825
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.
Figure 17.
Figure 18.
Figure 19.
Figure 20.
Figure 21.
Figure 22.
Figure 23.
Figure 24.
Figure 25.
Figure 26.
Figure 27.
Logic diagram (STM6821/6822/6823) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Logic diagram (STM6321/6322/6824/6825) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
STM6822/6823 SOT23-5 connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
STM6821 SOT23-5 connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
STM6322/6825 SOT23-5 connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
STM6321/6824 SOT23-5 connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Block diagram (STM6821/6822/6823) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Block diagram (STM6321/6824) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Block diagram (STM6322/6825) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Hardware hookup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
STM6321/6322/6822 open drain RST output with multiple supplies . . . . . . . . . . . . . . . . . 10
Ensuring RST valid to V
CC
= 0, (active-low push-pull outputs). . . . . . . . . . . . . . . . . . . . . . 12
Ensuring RST valid to V
CC
= 0, (active-high, push-pull outputs) . . . . . . . . . . . . . . . . . . . . 12
Interfacing to microprocessors with bidirectional reset I/O . . . . . . . . . . . . . . . . . . . . . . . . . 12
V
CC
-to-reset output delay vs. temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Supply current vs. temperature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
MR-to-reset output delay vs. temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Normalized power-up t
rec
vs. temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Normalized reset threshold voltage vs. temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Normalized power-up watchdog time-out period . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Voltage output low vs. I
SINK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Voltage output high vs. I
SOURCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Maximum transient duration vs. reset threshold overdrive . . . . . . . . . . . . . . . . . . . . . . . . . 17
AC testing input/output waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
MR timing waveform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Watchdog timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
SOT23-5 – 5-lead small outline transistor package mechanical drawing . . . . . . . . . . . . . . 23
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STM6321/6322STM6821/6822/6823/6824/6825
Description
1
Description
The STM6xxx supervisors are self-contained devices which provide microprocessor
supervisory functions. A precision voltage reference and comparator monitors the V
CC
input
for an out-of-tolerance condition. When an invalid V
CC
condition occurs, the reset output
(RST) is forced low (or high in the case of RST). These devices also offer a watchdog timer
(except for STM6322/6825) and/or a push-button (MR) reset input.
These devices are available in a standard 5-pin SOT23 package.
Figure 1.
Logic diagram (STM6821/6822/6823)
V
CC
WDI
STM6XXX
MR
RST (RST)
(1)
V
SS
AI09128
1. For STM6821 only.
Figure 2.
Logic diagram (STM6321/6322/6824/6825)
V
CC
RST
(WDI)
(1)
MR
STM6XXX
RST
V
SS
AI09129
1. For STM6321/6824.
Table 2.
MR
WDI
RST
RST
V
CC
V
SS
Signal names
Push-button reset input
Watchdog input
Active-low reset output
Active-high reset output
Supply voltage
Ground
5/28
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