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参数资料
| 型号： | SP809EK-L-2-9/TR |
| 厂商： | EXAR CORP |
| 元件分类： | 电源管理 |
| 英文描述： | 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO3 |
| 封装： | LEAD FREE, MO-178, SOT-23, 3 PIN |
| 文件页数： | 6/8页 |
| 文件大小： | 473K |
| 代理商： | SP809EK-L-2-9/TR |
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2011 Exar Corporation
6/8
Rev. 2.0.0
THEORY OF OPERATION
μP will be activated at a valid reset state.
These μP supervisory circuits assert reset to
prevent code execution errors during power-
up, power-down, or brownout conditions.
Reset is guaranteed to be a logic low for
VTH>VCC>0.9V. Once VCC exceeded the reset
threshold, an internal timer keeps RESET low
for the reset timeout period; after this interval,
RESET goes high.
If a brownout condition occurs (VCC drops
below the reset threshold), RESET goes low.
Any time VCC goes below the reset threshold,
the internal timer resets to zero, and RESET
goes low. The internal timer is activated after
VCC returns above the reset threshold, and
RESET remains low for the reset timeout
period.
BENEFIT OF HIGHLY ACCURATE RESET
THRESHOLD
SP809/810 with specified voltage as 5V±10%
or 3V±10% are ideal for systems using a
5V±5% or 3V±5% power supply. The reset is
guaranteed to assert after the power supply
falls below the minimum specified operating
voltage range of the system ICs. The pre-
trimmed thresholds are reducing the range
over which an undesirable reset may occur.
APPLICATION INFORMATION
NEGATIVE GOING VCC TRANSIENTS
In addition to issuing a reset to the P during
power-up,
power-down,
and
brownout
conditions,
SP809
series
are
relatively
resistant to short-duration negative-going VCC
transient.
ENSURING A VALID RESET OUTPUT DOWN
TO
VCC=0
When VCC falls below 0.9V, SP809 RESET
output no longer sinks current; it becomes an
open circuit. In this case, high-impedance
CMOS logic inputs connecting to RESET can
drift to undetermined voltages. Therefore,
SP809/810 with CMOS is perfect for most
applications of VCC down to 0.9V.
However in applications where RESET must be
valid down to 0V, adding a pull-down resistor
to RESET causes any leakage currents to flow
to ground, holding RESET low.
INTERFACING TO P WITH BIDIRECTIONAL
RESET PINS
The RESET output on the SP809N is open
drain, this device interfaces easily with μPs
that have bidirectional reset pins. Connecting
the μP supervisor's RESET output directly to
the microcontroller's RESET pin with a single
pull-up resistor allows either device to assert
reset.
TEST CIRCUIT
Fig. 10: Test Circuit
相关PDF资料 |
PDF描述 |
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| SP8481KP | 8-CH 12-BIT SUCCESSIVE APPROXIMATION ADC, PARALLEL ACCESS, PDIP32 |
| SP8481KS | 8-CH 12-BIT SUCCESSIVE APPROXIMATION ADC, PARALLEL ACCESS, PDSO32 |
| SP8481BP | 8-CH 12-BIT SUCCESSIVE APPROXIMATION ADC, PARALLEL ACCESS, PDIP32 |
| SP8481BS | 8-CH 12-BIT SUCCESSIVE APPROXIMATION ADC, PARALLEL ACCESS, PDSO32 |
| SP8481JP | 8-CH 12-BIT SUCCESSIVE APPROXIMATION ADC, PARALLEL ACCESS, PDIP32 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| SP809EK-L-3-1/TR | 功能描述:监控电路 3 PIN MICROPROCESSOR RESET CIRCUIT RoHS:否 制造商:STMicroelectronics 监测电压数: 监测电压: 欠电压阈值: 过电压阈值: 输出类型:Active Low, Open Drain 人工复位:Resettable 监视器:No Watchdog 电池备用开关:No Backup 上电复位延迟（典型值）:10 s 电源电压-最大:5.5 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:UDFN-6 封装:Reel |
| SP809EK-L-4-6/TR | 功能描述:监控电路 3 PIN MICROPROCESSOR RESET CIRCUIT RoHS:否 制造商:STMicroelectronics 监测电压数: 监测电压: 欠电压阈值: 过电压阈值: 输出类型:Active Low, Open Drain 人工复位:Resettable 监视器:No Watchdog 电池备用开关:No Backup 上电复位延迟（典型值）:10 s 电源电压-最大:5.5 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:UDFN-6 封装:Reel |
| SP809N | 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:3 Pin Microprocessor Supervisor Circuit |
| SP809NEK-2.3 | 制造商:Exar Corporation 功能描述:Voltage Detector |
| SP809NEK-2.6 | 制造商:Exar Corporation 功能描述:Voltage Detector |
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