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参数资料
| 型号： | AP1702FTW |
| 厂商： | DIODES INC |
| 元件分类： | 电源管理 |
| 英文描述： | 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO3 |
| 封装： | LEAD FREE, TSOT-23, 3 PIN |
| 文件页数： | 4/9页 |
| 文件大小： | 190K |
| 代理商： | AP1702FTW |
AP1701/2/3/4
3-Pin Microprocessor Reset Circuits
Anachip Corp.
www.anachip.com.tw
Rev. 1.4 Nov. 10, 2005
4/9
Function Description
A microprocessor’s (P’s) reset input starts the P
in a known state. The AP1701/2/3/4 assert reset to
prevent code-execution errors during power-up,
power-down, or brownout conditions. They assert a
reset signal whenever the VCC supply voltage
declines below a preset threshold, keeping it
asserted for at least 240ms after VCC has risen
above the reset threshold. The AP1701/2/3/4 have
a push-pull output stage.
Applications Information
Negative-Going VCC Transients
In addition to issuing a reset to the P during
power-up, power-down, and brownout conditions,
the
AP1701/2/3/4
are
relatively
immune
to
short-duration
negative-going
VCC
transients
(glitches).
The AP1701/2/3/4 do not generate a reset pulse.
The graph was generated using a negative going
pulse applied to VCC, starting 0.5V above the
actual reset threshold and ending below it by the
magnitude indicated (reset comparator overdrive).
The graph indicates the maximum pulse width a
negative going VCC transient can have without
causing a reset pulse. As the magnitude of the
transient increases (goes farther below the reset
threshold), the maximum allowable pulse width
decreases. Typically, a VCC transient that goes
100mV below the reset threshold and lasts 100s
or less will not cause a reset pulse. A 0.1F bypass
capacitor mounted as close as possible to the VCC
pin provides additional transient immunity.
Ensuring a Valid Reset Output
Down to VCC = 0
RESET
is guaranteed to be a logic low for VCC >
1V. Once VCC exceeds 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 dips
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 starts after VCC returns above
the reset threshold, and RESET remains low for
the reset timeout period.
When VCC falls below 1V, the AP1701/3 RESET
output 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 P and other circuitry is inoperative with VCC
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 AP1702/4 if RESET is required to
remain valid for VCC < 1V.
Benefits of Highly Accurate Reset Threshold
Most P supervisor ICs have reset threshold
voltages between 5% and 10% below the value of
nominal sup-ply 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.
This Anachip version datasheet is replaced
with Diodes Inc. datasheet AP1701/2/3/4
Actual Package is SC-59, not SOT-23
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相关代理商/技术参数 |
参数描述 |
|---|---|
| AP1702FW | 制造商:ANACHIP 制造商全称:Anachip Corp 功能描述:3-Pin Microprocessor Reset Circuits |
| AP1702FWG-7 | 功能描述:监控电路 INTRF RESET HIGH CMOS 1.0V-5.5V 2.63V 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 |
| AP1702FWL | 制造商:ANACHIP 制造商全称:Anachip Corp 功能描述:3-Pin Microprocessor Reset Circuits |
| AP1702FWL-7 | 制造商:DIODES 制造商全称:Diodes Incorporated 功能描述:3-PIN MICROPROCESSOR RESET CIRCUITS |
| AP1702GSAL-7 | 功能描述:监控电路 INTRF RESET HIGH CMOS 1.1V-6.0V 2.25V 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 |
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