參數(shù)資料
型號(hào): LM2672M-3.3X
廠商: NATIONAL SEMICONDUCTOR CORP
元件分類: 穩(wěn)壓器
英文描述: 2.2 A SWITCHING REGULATOR, 275 kHz SWITCHING FREQ-MAX, PDSO8
封裝: 0.150 INCH, PLASTIC, SO-8
文件頁數(shù): 4/26頁
文件大小: 626K
代理商: LM2672M-3.3X
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
相關(guān)PDF資料
PDF描述
LM2672M-5.0X 2.2 A SWITCHING REGULATOR, 275 kHz SWITCHING FREQ-MAX, PDSO8
LM2672LD-5.0/NOPB 2.2 A SWITCHING REGULATOR, 275 kHz SWITCHING FREQ-MAX, PDSO16
LM2672M-ADJX 2.2 A SWITCHING REGULATOR, 275 kHz SWITCHING FREQ-MAX, PDSO8
LM2674-3.3MDC 1.25 A SWITCHING REGULATOR, 275 kHz SWITCHING FREQ-MAX, UUC
LM2674-3.3MWC 1.25 A SWITCHING REGULATOR, 275 kHz SWITCHING FREQ-MAX, UUC
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LM2672M-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
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/直流開關(guān)轉(zhuǎn)換器 HIGH EFF 1A STEP- DOWN VLTG REG 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
LM2672M-ADJ 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
LM2672M-ADJ 制造商:Texas Instruments 功能描述:SWITCHING REG 1A ADJ 2672 SOIC8