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参数资料
| 型号： | LM3724EM5X-3.08/NOPB |
| 厂商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分类： | 电源管理 |
| 英文描述： | 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO5 |
| 封装： | SOT-23, 5 PIN |
| 文件页数： | 10/12页 |
| 文件大小： | 290K |
| 代理商： | LM3724EM5X-3.08/NOPB |
Timing Diagram
20014412
Circuit Information
RESET OUTPUT
The reset input of a P initializes the device into a known
state. The LM3722/LM3723/LM3724 microprocessor voltage
monitoring circuits assert a forced reset output to prevent
code execution errors during power-up, power-down, and
brownout conditions.
RESET is guaranteed valid for V
CC ≥ 1V. Once VCC exceeds
the reset threshold, an internal timer maintains the output for
the reset timeout period. After this interval, reset goes high
and the microprocessor initializes itself into a known state.
The LM3722 and LM3724 offer an active-low RESET; the
LM3723 offers an active-high RESET.
As V
CC drops below the reset threshold (such as during a
brownout), the reset activates (see the Negative-Going V
CC
Transients section). When V
CC again rises above the reset
threshold, the internal timer starts. Reset holds until V
CC ex-
ceeds the reset threshold for longer than the reset timeout
period. After this time, reset releases.
Additionally, the Manual Reset input (MR) will initiate a forced
reset. See the Manual Reset Input section.
The LM3722/LM3723/LM3724 reset outputs ignore short du-
ration glitches on V
CC and MR. See the Applications Informa-
tion section for details.
RESET THRESHOLD
The LM3722/LM3723/LM3724 are available with reset volt-
ages of 4.63V, 3.08V, and 2.32V which are suitable for mon-
itoring 5.0V, 3.3V, and 2.5V supplies respectively. Other reset
thresholds in the 2.20V to 5.0V range, in 10 mV steps, are
available; contact National Semiconductor for details.
MANUAL RESET INPUT (MR)
Many P-based products require a manual reset capability,
allowing the operator to initiate a reset. The MR input is fully
debounced and provides an internal 22 k
pull-up. When the
MR input is pulled below V
IL (0.25VCC) for more than 100 ns,
reset is asserted after a typical delay of 2 s. Reset remains
active as long as MR is held low, and releases after MR rises
above V
IH and the reset timeout period expires. Use MR with
digital logic to assert reset or to daisy chain supervisory cir-
cuits.
Applications Information
BENEFITS OF PRECISION RESET THRESHOLDS
A microprocessor supply supervisor must provide a reset out-
put within a predictable range of the supply voltage. A com-
mon threshold range is between 5% and 10% below the
nominal supply voltage. The 4.63V, 3.08V and 2.32V options
of the LM3722/LM3723/LM3724 use highly accurate circuitry
to ensure that the reset threshold occurs only within this range
(for 5.0V, 3.3V and 2.5V supplies). Table 1 shows how the
standard reset thresholds apply to 5.0V, 3.3V, and 2.5V nom-
inal supply voltages.
7
www.national.com
LM3722/LM3723/LM3724
相关PDF资料 |
PDF描述 |
|---|---|
| LM3724EM5-2.32/NOPB | 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO5 |
| LM3722EM5-4.63/NOPB | 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO5 |
| LM3722EM5X-3.08/NOPB | 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO5 |
| LM3722IM5X-3.08/NOPB | 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO5 |
| LM3723EM5-4.63/NOPB | 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO5 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LM3724EM5X-4.63 | 功能描述:监控电路 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 |
| LM3724EM5X-4.63/NOPB | 功能描述:监控电路 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 |
| LM3724IM5-2.32 | 制造商:Texas Instruments 功能描述:RESET CIRCUIT SMD 3724 SOT-23-5 制造商:Texas Instruments 功能描述:RESET CIRCUIT, SMD, 3724, SOT-23-5 |
| LM3724IM5-2.32 | 制造商:Texas Instruments 功能描述:RESET CIRCUIT SMD 3724 SOT-23-5 |
| LM3724IM5-2.32/NOPB | 功能描述:监控电路 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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