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参数资料
| 型号： | 795S |
| 厂商： | 意法半导体 |
| 英文描述： | 3V Supervisor with Battery Switchover |
| 中文描述： | 3V的监控与电池切换 |
| 文件页数： | 11/32页 |
| 文件大小： | 304K |
| 代理商： | 795S |
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STM690/704/795/802/804/805/806
Power-fail Input/Output (NOT available on STM795)
The Power-fail Input (PFI) is compared to an inter-
nal reference voltage (independent from the V
RST
comparator). If PFI is less than the power-fail
threshold (V
PFI
), the Power-Fail Output (PFO) will
go low. This function is intended for use as an un-
dervoltage detector to signal a failing power sup-
ply. Typically PFI is connected through an external
voltage divider (see
Figure 11., page 8
) to either
the unregulated DC input (if it is available) or the
regulated output of the V
CC
regulator. The voltage
divider can be set up such that the voltage at PFI
falls below V
PFI
several milliseconds before the
regulated V
CC
input to the STM690/704/795/802/
804/805/806 or the microprocessor drops below
the minimum operating voltage.
During battery back-up, the power-fail comparator
is turned off and PFO goes (or remains) low (see
Figure 14., page 11
). This occurs after V
CC
drops
below V
SW
(2.4V). When power returns, the pow-
er-fail comparator is enabled and PFO follows PFI.
If the comparator is unused, PFI should be con-
nected to V
SS
and PFO left unconnected. PFO
may be connected to MR on the STM704/806 so
that a low voltage on PFI will generate a reset out-
put.
Applications Information
These Supervisor circuits are not short-circuit pro-
tected. Shorting V
OUT
to ground - excluding pow-
er-up transients such as charging a decoupling
capacitor - destroys the device. Decouple both
V
CC
and V
BAT
pins to ground by placing 0.1μF ca-
pacitors as close to the device as possible.
Figure 14. Power-fail Comparator Waveform (STM690/704/802/804/805/806)
AI08861a
VCC
VRST
VSW (2.4V)
trec
RST
PFO
PFO follows PFI
PFO follows PFI
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相关代理商/技术参数 |
参数描述 |
|---|---|
| 795T | 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:3V Supervisor with Battery Switchover |
| 795XFL-2 CAL | 制造商:Starrett Company 功能描述:CALIBRATED - 1-2" 25-50MM ELECTRONIC MICROMETER WITH OUTPUT |
| 795XFL-2 CAL DU | 制造商:Starrett Company 功能描述:CALIBRATED W/ DATA & UNCERTAINTIES - 1-2" 25-50MM ELECTRONIC MICROMETER WITH OUT |
| 796 | 功能描述:电路板硬件 - PCB NYL Rd Clr Hle Spcr 1.00 .312OD #10 RoHS:否 制造商:Harwin 类型:Shield Clip 长度:9.4 mm 螺纹大小: 外径: 材料:Beryllium Copper 电镀:Tin |
| 79600 | 制造商:Amphenol 功能描述:AMPHENOL TNC JACK S9B2B 制造商:TE Connectivity 功能描述: |
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