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參數(shù)資料
| 型號： | LM3670MFX-3.3 |
| 廠商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | Miniature Step-Down DC-DC Converter for Ultra Low Voltage Circuits |
| 中文描述： | 0.75 A SWITCHING REGULATOR, 1300 kHz SWITCHING FREQ-MAX, PDSO5 |
| 封裝： | SOT-23, 5 PIN |
| 文件頁數(shù)： | 10/17頁 |
| 文件大?。?/td> | 997K |
| 代理商： | LM3670MFX-3.3 |
Typical Performance Characteristics
(unless otherwise stated: V
IN
=3.6V, V
OUT
=1.8V) (Continued)
PFM Mode
V
SW
, V
OUT
, I
INDUCTOR
vs. Time
PWM Mode
V
SW
, V
OUT
, I
INDUCTOR
vs. Time
20075822
20075823
Soft Start
V
IN
, V
OUT
, I
INDUCTOR
vs. Time
LOAD
20075824
Operation Description
DEVICE INFORMATION
The LM3670, a high efficiency step down DC-DC switching
buck converter, delivers a constant voltage from either a
single Li-Ion or three cell NiMH/NiCd battery to portable
devices such as cell phones and PDAs. Using a voltage
mode
architecture
with
synchronous
LM3670 has the ability to deliver up to 350 mAdepending on
the input voltage and output voltage (voltage head room),
and the inductor chosen (maximum current capability).
There are three modes of operation depending on the cur-
rent required - PWM, PFM, and shutdown. PWM mode
handles current loads of approximately 70 mA or higher.
Lighter output current loads cause the device to automati-
cally switch into PFM for reduced current consumption (I
=
15 μAtyp) and a longer battery life. Shutdown mode turns off
the
device,
offering
the
lowest
(I
Q, SHUTDOWN
= 0.1 μA typ).
rectification,
the
current
consumption
The LM3670 can operate up to a 100% duty cycle (PMOS
switch always on) for low drop out control of the output
voltage. In this way the output voltage will be controlled
down to the lowest possible input voltage.
Additional features include soft-start, under voltage lock out,
current overload protection, and thermal overload protection.
As shown in
Figure 1
, only three external power components
are required for implementation.
CIRCUIT OPERATION
The LM3670 operates as follows. During the first portion of
each switching cycle, the control block in the LM3670 turns
on the internal PFET switch. This allows current to flow from
the input through the inductor to the output filter capacitor
and load. The inductor limits the current to a ramp with a
slope of
by storing energy in a magnetic field. During the second
portion of each cycle, the controller turns the PFET switch
L
www.national.com
10
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PDF描述 |
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| LM3670MFX-ADJ | Miniature Step-Down DC-DC Converter for Ultra Low Voltage Circuits |
| LM3670MF-2.5 | Miniature Step-Down DC-DC Converter for Ultra Low Voltage Circuits |
| LM3670MF-3.3 | Miniature Step-Down DC-DC Converter for Ultra Low Voltage Circuits |
| LM3670MF-ADJ | Miniature Step-Down DC-DC Converter for Ultra Low Voltage Circuits |
| LM3670MF-1.5 | Miniature Step-Down DC-DC Converter for Ultra Low Voltage Circuits |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LM3670MFX-ADJ | 制造商:Rochester Electronics LLC 功能描述: 制造商:Texas Instruments 功能描述: |
| LM3670MFX-ADJ/NOPB | 功能描述:DC/DC 開關(guān)控制器 RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風(fēng)格: 封裝 / 箱體:CPAK |
| LM3671 | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:2MHz , 600mA Step-Down DC-DC Converter in SOT23-5 |
| LM3671_07 | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:2MHz, 600mA Step-Down DC-DC Converter |
| LM3671_08 | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:2MHz, 600mA Step-Down DC-DC Converter |
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