參數(shù)資料
型號(hào)： STM1813L
廠商： 意法半導(dǎo)體
英文描述： Low Power Reset Circuit
中文描述： 低功耗復(fù)位電路
文件頁(yè)數(shù)： 7/20頁(yè)
文件大?。?/td> 321K
代理商： STM1813L
7/20
STM1810/1811/1812/1813/1815/1816/1817/1818
OPERATION
Reset Output
The STM181x asserts a reset signal to the Micro-
controller (MCU) whenever V
CC
goes below the
reset threshold (V
RST
), and is guaranteed valid
down to V
CC
= 1.0V (0° to 105°C). A microcontrol-
ler’s (MCU) reset input starts the MCU in a known
state. The STM1810 - STM1813/ STM1815 -
STM1818 Low Power Reset circuits assert reset to
prevent code-execution errors during power-up,
power-down, and brownout conditions (
Figure
8., page 7
).
During power-up, once V
CC
exceeds the reset
threshold an internal timer keeps RST low for the
reset time-out period, t
rec
. After this interval, RST
returns high.
If V
CC
drops below the reset threshold, RST goes
low. Each time RST is asserted, it stays low for at
least the reset time-out period. Any time V
CC
goes
below the reset threshold, the internal timer clears.
The reset timer starts when V
CC
returns above the
reset threshold. Reset t
rec
is also triggered by an
externally initiated rising edge on the RST pin
(STM1813/STM1818), following a low signal of
1.5μs minimum duration.
Push-Button Detect Reset (STM1813/1818)
Many systems require push-button reset capability
(
Figure 9., page 8
), allowing the user or external
logic circuitry to initiate reset. On the STM1813/
STM1818, a logic low on RST held for greater than
1.5μs asserts a reset. RST deasserts following a
100ms minimum reset time-out delay (t
rec
). A
manual reset input shorter than 1.5μs may release
RST without the 100ms minimum reset time-out
delay. To facilitate use with mechanical switches,
the STM1813/STM1818 contain internal de-
bounce circuitry. A debounced waveform is shown
in
Figure 10., page 8
The RST output has an inter-
nal 5.5k
pull-up resistor.
Interfacing to Bidirectional Microcontrollers
(MCU’s)
As the RST output on the STM1811/STM1816 is
open drain, these devices interface easily with
MCU’s that have bidirectional reset pins. Connect-
ing the μP supervisor’s reset (RST) output directly
to the microcontroller’s reset (RST) pin allows ei-
ther device to assert reset (
Figure 11., page 8
). No
external pull-up resistor is required, as it is within
the STM1811/STM1816.
Negative Going V
CC
Transients
The STM181x are relatively immune to negative-
going
V
CC
transients
20., page 13
shows typical transient duration ver-
sus reset comparator overdrive (for which the
STM181x will NOT generate a reset pulse). The
graph was generated using a negative pulse ap-
plied to V
CC,
starting at 0.5V above the actual re-
set threshold and ending below it by the
magnitude indicated (comparator overdrive). The
graph indicates the maximum pulse width a nega-
tive V
CC
transient can have without causing a re-
set pulse. As the magnitude of the transient
increases (further below the threshold), the maxi-
mum allowable pulse width decreases. Any com-
bination of duration and overdrive which lies under
the curve will NOT generate a reset signal. Typi-
cally, a V
CC
transient that goes 100mV below the
reset threshold and lasts 20μs or less will not
cause a reset pulse. A 0.1μF bypass capacitor
mounted as close as possible to the V
CC
pin pro-
vides additional transient immunity.
Valid RST Output Down to V
CC
= 0V
When V
CC
falls below 1V, the RST output no long-
er sinks current, but becomes an open circuit. In
most systems this is not a problem, as most MCUs
do not operate below 1V. However, in applications
where RST output must be valid down to 0V, a
pull-down resistor may be added to hold the RST
output low (see
Figure 12., page 9
). This resistor
must be large enough to not load the RST output,
and still be small enough to pull the output to
ground. A 100k
resistor is recommended.
Note:
The same situation applies for the active-
high RST of the STM1810/1812. A 100k
pull-up
resistor to V
CC
should be used if RST must remain
valid for V
CC
< 1.0V.
(glitches).
Figure
Figure 8. Reset Timing Diagram
Note: 1. RST for STM1812 and STM1817
AI09653
RST
RST
(1)
VCC
VRST
VCC (min)
trec
trec
相關(guān)PDF資料
PDF描述
STM1813M Low Power Reset Circuit
STM1810 Low Power Reset Circuit
STM1810L Low Power Reset Circuit
STM1810M Low Power Reset Circuit
STM1811 Low Power Reset Circuit
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
STM1813LRWX7F 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:Low power reset circuit
STM1813LSWX7F 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:Low power reset circuit
STM1813LTWX7F 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:Low power reset circuit
STM1813LWX7F 功能描述:監(jiān)控電路 4.62VRST Active Low Open Drain reset RoHS:否 制造商:STMicroelectronics 監(jiān)測(cè)電壓數(shù): 監(jiān)測(cè)電壓: 欠電壓閾值: 過電壓閾值: 輸出類型:Active Low, Open Drain 人工復(fù)位:Resettable 監(jiān)視器:No Watchdog 電池備用開關(guān):No Backup 上電復(fù)位延遲（典型值）:10 s 電源電壓-最大:5.5 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:UDFN-6 封裝:Reel
STM1813LWX7F-CUT TAPE 制造商:ST 功能描述:STM1813 Series 4.62 V 100 ms Surface Mount Low Power Reset Circuit - SOT-23
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。

采購(gòu)需求

(若只采購(gòu)一條型號(hào)，填寫一行即可)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

*型號(hào) *數(shù)量 廠商 批號(hào) 封裝
添加更多采購(gòu)

我的聯(lián)系方式

*
*
*