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参数资料
| 型号： | LM2672M-12X |
| 厂商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分类： | 稳压器 |
| 英文描述： | 2.2 A SWITCHING REGULATOR, 275 kHz SWITCHING FREQ-MAX, PDSO8 |
| 封装： | 0.150 INCH, PLASTIC, SO-8 |
| 文件页数： | 4/26页 |
| 文件大小： | 626K |
| 代理商： | LM2672M-12X |
PROCEDURE (Fixed Output Voltage Version)
EXAMPLE (Fixed Output Voltage Version)
5. Boost Capacitor (C
B)
This capacitor develops the necessary voltage to turn the switch
gate on fully. All applications should use a 0.01
μF, 50V ceramic
capacitor.
5. Boost Capacitor (C
B)
For this application, and all applications, use a 0.01
μF, 50V
ceramic capacitor.
6. Soft-Start Capacitor (C
SS - optional)
This capacitor controls the rate at which the device starts up. The
formula for the soft-start capacitor C
SS is:
6. Soft-Start Capacitor (C
SS - optional)
For this application, selecting a start-up time of 10 ms and using
the formula for C
SS results in a value of:
where:
I
SS
= Soft-Start Current
:4.5 μA typical.
t
SS
= Soft-Start Time
:Selected.
V
SSTH
= Soft-Start Threshold Voltage
:0.63V typical.
V
OUT
= Output Voltage
:Selected.
V
SCHOTTKY
= Schottky Diode Voltage Drop
:0.4V typical.
V
IN
= Input Voltage
:Selected.
If this feature is not desired, leave this pin open. With certain
softstart capacitor values and operating conditions, the LM2672
can exhibit an overshoot on the output voltage during turn on.
Especially when starting up into no load or low load, the softstart
function may not be effective in preventing a larger voltage
overshoot on the output. With larger loads or lower input voltages
during startup this effect is minimized. In particular, avoid using
softstart capacitors between 0.033F and 1F.
7. Frequency Synchronization (optional)
The LM2672 (oscillator) can be synchronized to run with an
external oscillator, using the sync pin (pin 3). By doing so, the
LM2672 can be operated at higher frequencies than the standard
frequency of 260 kHz. This allows for a reduction in the size of the
inductor and output capacitor.
As shown in the drawing below, a signal applied to a RC filter at the
sync pin causes the device to synchronize to the frequency of that
signal. For a signal with a peak-to-peak amplitude of 3V or greater,
a 1 k
resistor and a 100 pF capacitor are suitable values.
7. Frequency Synchronization (optional)
For all applications, use a 1 k
resistor and a 100 pF capacitor for
the RC filter.
www.national.com
12
LM2672
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LM2672M-3.3 | 功能描述:直流/直流开关转换器 RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| LM2672M-3.3/NOPB | 功能描述:直流/直流开关转换器 HIGH EFF 1A STEP- DOWN VLTG REG RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| LM2672M-5.0 | 功能描述:直流/直流开关转换器 RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| LM2672M-5.0 | 制造商:Texas Instruments 功能描述:SWITCHING REG 1A 5.0V 2672 SOIC8 |
| LM2672M-5.0/NOPB | 功能描述:直流/直流开关转换器 HIGH EFF 1A STEP- DOWN VLTG REG RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
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