參數(shù)資料
型號： LM2597M-12
廠商： NATIONAL SEMICONDUCTOR CORP
元件分類： 穩(wěn)壓器
英文描述： SIMPLE SWITCHER Power Converter 150 kHz 0.5A Step-Down Voltage Regulator, with Features
中文描述： 1.4 A SWITCHING REGULATOR, 173 kHz SWITCHING FREQ-MAX, PDSO8
封裝： PLASTIC, SOIC-8
文件頁數(shù)： 22/34頁
文件大?。?/td> 900K
代理商： LM2597M-12
Application Information
(Continued)
DELAY CAPACITOR
C
—Provides delay for the error flag output. See the
upper curve in Figure 13 and also refer to timing diagrams in
Figure 14 A capacitor on this pin provides a time delay
between the time the regulated output voltage (when it is
increasing in value) reaches 95% of the nominal output
voltage, and the time the error flag output goes high. A 3 μA
constant current from the delay pin charges the delay ca-
pacitor resulting in a voltage ramp. When this voltage
reaches a threshold of approximately 1.3V, the open collec-
tor error flag output (or power OK) goes high. This signal can
be used to indicate that the regulated output has reached the
correct voltage and has stabilized.
If, for any reason, the regulated output voltage drops by 5%
or more, the error output flag (Pin 1) immediately goes low
(internal transistor turns on). The delay capacitor provides
very little delay if the regulated output is dropping out of
regulation. The delay time for an output that is decreasing is
approximately a 1000 times less than the delay for the rising
output. For a 0.1 μF delay capacitor, the delay time would be
approximately 50 ms when the output is rising and passes
through the 95% threshold, but the delay for the output
dropping would only be approximately 50 μs.
R
—The error flag output, (or power OK) is the col-
lector of a NPN transistor, with the emitter internally
grounded. To use the error flag, a pullup resistor to a positive
voltage is needed. The error flag transistor is rated up to a
maximum of 45V and can sink approximately 3 mA. If the
error flag is not used, it can be left open.
INPUT CAPACITOR
C
—A low ESR aluminum or tantalum bypass capacitor is
needed between the input pin and ground pin. It must be
located near the regulator using short leads. This capacitor
prevents large voltage transients from appearing at the in-
put, and provides the instantaneous current needed each
time the switch turns on.
The important parameters for the Input capacitor are the
voltage rating and the RMS current rating. Because of the
relatively high RMS currents flowing in a buck regulator’s
input capacitor, this capacitor should be chosen for its RMS
DS012440-34
FIGURE 14. Timing Diagram for 5V Output
DS012440-75
FIGURE 15. External 3.7V Soft-Start Clamp
L
www.national.com
22
相關(guān)PDF資料
PDF描述
LM2597N-3.3 SIMPLE SWITCHER Power Converter 150 kHz 0.5A Step-Down Voltage Regulator, with Features
LM2597 Octal Buffers/Drivers With 3-State Outputs 20-SO -40 to 85
LM2597HV
LM2608 400mA Sub-miniature, High Efficiency, Programmable DC-DC Converter with Linear Mode
LM2608ATL-1.3 400mA Sub-miniature, High Efficiency, Programmable DC-DC Converter with Linear Mode
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LM2597M-12/NOPB 功能描述:直流/直流開關(guān)轉(zhuǎn)換器 RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT
LM2597M-3.3 功能描述:直流/直流開關(guān)轉(zhuǎn)換器 RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT
LM2597M-3.3/NOPB 功能描述:直流/直流開關(guān)轉(zhuǎn)換器 RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT
LM2597M33 制造商:Texas Instruments 功能描述:SWITCHING REG 0.5A 3.3V SMD 2597
LM2597M-5.0 功能描述:直流/直流開關(guān)轉(zhuǎn)換器 RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。

采購需求

(若只采購一條型號，填寫一行即可)

發(fā)布成功！您可以繼續(xù)發(fā)布采購。也可以進(jìn)入我的后臺，查看報(bào)價

發(fā)布成功！您可以繼續(xù)發(fā)布采購。也可以進(jìn)入我的后臺，查看報(bào)價

*型號 *數(shù)量 廠商 批號 封裝
添加更多采購

我的聯(lián)系方式

*
*
*