- 您现在的位置：买卖IC网 > PDF目录44559 > LM3724EM5X-3.08/NOPB (NATIONAL SEMICONDUCTOR CORP) 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO5 PDF资料下载
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： | 11/12页 |
| 文件大小： | 290K |
| 代理商： | LM3724EM5X-3.08/NOPB |
TABLE 1. Monitored Tolerance Table
Reset
Threshold
Supply Voltage
2.5V
3.3V
5.0V
4.63 ± %
90.8-94.4
%
3.08 ± %
91.8-95.2
%
2.32 ± %
90.8-94.8
%
ENSURING A VALID RESET OUTPUT DOWN TO V
CC = 0V
When V
CC falls below 1V, the LM3722 RESET output is un-
able to sink the rated current. A high-impedance CMOS logic
input connected to RESET can therefore drift to undetermined
voltages. To prevent this situation, a 100k
Ω resistor should
be connected from the RESET output to ground, as shown in
A 100k
Ω pull-up resistor to V
CC is also recommended for the
LM3723, if RESET is required to remain valid for V
CC < 1V.
20014410
FIGURE 1. Circuit for RESET Valid from V
CC = 0V
OPEN DRAIN OUTPUT (LM3724)
An open drain output allows easy paralleling of multiple mi-
croprocessor reset circuits without requiring additional logic
gates. Open drain outputs also allow interfacing devices of
differing logic levels or families, since the output pull-up re-
sistor may be connected to any supply voltage up to 5.5V,
regardless of LM3724 V
CC.
The pull up resistor is calculated so that maximum current flow
into RESET is less than 10 mA when activated. The resistor
must be small enough so that the leakage current of all con-
nected devices does not create an excessive voltage drop
when the output is not activated. A resistor value of 100 k
will generally suffice.
NEGATIVE-GOING V
CC TRANSIENTS
The LM3722/LM3723/LM3724 are relatively immune to short
negative-going transients or glitches on V
CC. Figure 2 shows
the maximum pulse width a negative-going V
CC transient can
have without causing a reset pulse. In general, as the mag-
nitude of the transient increases, going further below the
threshold, the maximum allowable pulse width decreases.
Typically, a V
CC transient that goes 125 mV below the reset
threshold and lasts 40 s or less will not cause a reset pulse.
A 0.1 F bypass capacitor mounted as close as possible to
the V
CC pin will provide additional transient rejection.
20014414
FIGURE 2. Maximum Transient Duration without Causing
a Reset Pulse vs. Reset Comparator Overdrive
INTERFACING TO PS WITH BIDIRECTIONAL RESET
PINS
Microprocessors with bidirectional reset pins, such as the
Motorola 68HC11 series, can be connected to the LM3722
RESET output. To ensure a correct output on the LM3722
even when the microprocessor reset pin is in the opposite
state, connect a 4.7k
Ω resistor between the LM3722 RE-
SET output and the P reset pin, as shown in Figure 3. Buffer
the LM3722 RESET output to other system components.
www.national.com
8
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 |
发布紧急采购，3分钟左右您将得到回复。