参数资料
| 型号： | APX812-44UG-7 |
| 厂商： | Diodes Inc |
| 文件页数： | 7/10页 |
| 文件大小： | 0K |
| 描述： | IC SUPERVISOR 4.38V SOT143-4 |
| 标准包装： | 3,000 |
| 类型： | 简单复位/加电复位 |
| 监视电压数目： | 1 |
| 输出： | 推挽式，图腾柱 |
| 复位： | 高有效 |
| 复位超时： | 最小为 140 ms |
| 电压 - 阀值： | 4.38V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | TO-253-4，TO-253AA |
| 供应商设备封装： | SOT-143 |
| 包装： | 带卷 (TR) |
APX811/812
4-Pin Microprocessor Supervisor With Manual Reset
Application Information
A microprocessor’s (μP’s) reset input starts the μP in a known state. The APX811/812 asserts reset to prevent code-execution errors
during power-up, power-down, or brownout conditions. They assert a reset signal whenever the V CC supply voltage declines below a
preset threshold or the MR pin is brought low, keeping it asserted for at least 240ms after V CC has risen above the reset threshold. The
APX811/812 have a push-pull output stage.
The APX811/812 reset output is guaranteed to be logic low for the APX811 and high the APX812 for V CC > 1V. Once V CC exceeds the
reset threshold, an internal timer keeps RESET output low (and RESET high for the APX812) for the reset timeout period. After this
interval, the APX811’s RESET output goes high (APX812’s RESET output goes low). If a brownout condition occurs (V CC dips below the
reset threshold), the APX811’s RESET output goes low (APX812’s RESET output goes high). Any time V CC goes below the reset
threshold, the internal timer resets to zero, and RESET goes low (RESET goes high). The internal timer starts after V CC returns above
the reset threshold, and RESET remains low (RESET remains high) for the reset timeout period.
Ensuring a Valid Reset Output Down to V CC = 0
When V CC falls below 1V, the APX811 RESET no longer sinks current-— it becomes an open circuit. Therefore, high-impedance
CMOS logic inputs connected to RESET can drift to undetermined voltages. This presents no problem in most applications since most
μP and other circuitry is inoperative with V CC below 1V. However, in applications where RESET must be valid down to 0V, adding a pull
down resistor to RESET causes any stray leakage currents to flow to ground, holding RESET low. R1’s value is not critical; 100k is
large enough not to load RESET and small enough to pull RESET to ground.
For the APX812 if RESET is required to remain valid for V CC < 1V then a 100k ? pull-up resistor between RESET and V CC is
recommended.
Benefits of Highly Accurate Reset Threshold
Most μP supervisor ICs has reset threshold voltages between 5% and 10% below the value of nominal supply voltages. This ensures a
reset will not occur within 5% of the nominal supply, but will occur when the supply is 10% below nominal. When using ICs rated at only
the nominal supply ±5%, this leaves a zone of uncertainty where the supply is between 5% and 10% low, and where the reset may or may
not be asserted.
APX811/812 Rev. 2
DS31960
7 of 10
OCTOBER 2009
? Diodes Incorporated
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| APX812-46UG-7 | 功能描述:监控电路 4-PIN MPU SUPERVISOR 4.63V Active-High 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 |
| APX812-XXUG-7 | 制造商:DIODES 制造商全称:Diodes Incorporated 功能描述:4-Pin Microprocessor Supervisor With Manual Reset |
| APX823 | 制造商:DIODES 制造商全称:Diodes Incorporated 功能描述:PROCESSOR SUPERVISORY CIRCUITS |
| APX823-23W5G-7 | 功能描述:监控电路 1.1V-5.5V 2.25V 20mA 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 |
| APX823-23W6G-7 | 制造商:DIODES 制造商全称:Diodes Incorporated 功能描述:PROCESSOR SUPERVISORY CIRCUITS |
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