- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄377724 > LT3470ETS8 (Linear Integrated Systems) Micropower Buck Regulator with Integrated Boost and Catch Diodes PDF資料下載
參數(shù)資料
| 型號： | LT3470ETS8 |
| 廠商： | Linear Integrated Systems |
| 英文描述： | Micropower Buck Regulator with Integrated Boost and Catch Diodes |
| 中文描述： | 微功耗降壓穩(wěn)壓器與集成升壓二極管和捕捉 |
| 文件頁數(shù)： | 7/16頁 |
| 文件大?。?/td> | 205K |
| 代理商： | LT3470ETS8 |
7
LT3470
3470f
OPERATIOU
The LT3470 uses a hysteretic control scheme in conjunc-
tion with Burst Mode operation to provide low output
ripple and low quiescent current while using a tiny induc-
tor and capacitors.
Operation can best be understood by studying the Block
Diagram. An error amplifier measures the output voltage
through an external resistor divider tied to the FB pin. If
the FB voltage is higher than V
REF
, the error amplifier will
shut off all the high power circuitry, leaving the LT3470 in
its micropower state. As the FB voltage falls, the error
amplifier will enable the power section, causing the chip
to begin switching, thus delivering charge to the output
capacitor. If the load is light the part will alternate between
micropower and switching states to keep the output in
regulation (See Figure 1a). At higher loads the part will
switch continuously while the error amp servos the top
and bottom current limits to regulate the FB pin voltage to
1.25V (See Figure 1b).
The switching action is controlled by an RS latch and two
current comparators as follows: The switch turns on, and
the current through it ramps up until the top current
comparator trips and resets the latch causing the switch to
turn off. While the switch is off, the inductor current ramps
down through the catch diode. When both the bottom
current comparator trips and the minimum off-time one-
shot expires, the latch turns the switch back on thus
completing a full cycle. The hysteretic action of this control
scheme results in a switching frequency that depends on
inductor value, input and output voltage. Since the switch
only turns on when the catch diode current falls below
threshold, the part will automatically switch slower to keep
inductor current under control during start-up or short-
circuit conditions.
The switch driver operates from either the input or from
the BOOST pin. An external capacitor and internal diode is
used to generate a voltage at the BOOST pin that is higher
than the input supply. This allows the driver to fully
saturate the internal bipolar NPN power switch for efficient
operation.
If the SHDN pin is grounded, all internal circuits are turned
off and V
IN
current reduces to the device leakage current,
typically a few nA.
(1a) Burst Mode Operation
(1b) Continuous Operation
Figure 1. Operating Waveforms of the LT3470 Converting 12V to 5V Using a 33
μ
H Inductor and 10
μ
F Output Capacitor
V
20mV/DIV
I
L
100mA/DIV
1ms/DIV
V
20mV/DIV
I
L
100mA/DIV
5
μ
s/DIV
3470 F01a
NO LOAD
10mA LOAD
V
20mV/DIV
I
L
100mA/DIV
1
μ
s/DIV
V
20mV/DIV
I
L
100mA/DIV
1
μ
s/DIV
3470 F1b
200mA LOAD
150mA LOAD
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LT3470ITS8 | Micropower Buck Regulator with Integrated Boost and Catch Diodes |
| LTBDM | Micropower Buck Regulator with Integrated Boost and Catch Diodes |
| LT3486 | Dual 1.3A White LED Step-Up Converters with Wide Dimming |
| LT3486EDHC | Dual 1.3A White LED Step-Up Converters with Wide Dimming |
| LT3486EFE | Dual 1.3A White LED Step-Up Converters with Wide Dimming |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LT3470ETS8#PBF | 制造商:Linear Technology 功能描述:DC-DC CONVERTER BUCK ADJ 20 制造商:Linear Technology 功能描述:DC-DC CONVERTER, BUCK, ADJ, 200mA, TSOT-23-8; Primary Input Voltage:40V; No. of Outputs:1; Output Current:200mA; No. of Pins:8; Operating Temperature Min:-40C; Operating Temperature Max:85C; Package / Case:8-TSOT-23 ;RoHS Compliant: Yes |
| LT3470ETS8#TR | 制造商:Linear Technology 功能描述:Conv DC-DC Single Step Down 4V to 40V 8-Pin TSOT-23 T/R |
| LT3470ETS8#TRM | 制造商:Linear Technology 功能描述:Conv DC-DC Single Step Down 4V to 40V 8-Pin TSOT-23 T/R |
| LT3470ETS8#TRMPBF | 功能描述:IC REG BUCK ADJ 0.2A TSOT23-8 RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關(guān)穩(wěn)壓器 系列:- 標準包裝:250 系列:- 類型:降壓（降壓） 輸出類型:固定 輸出數(shù):1 輸出電壓:1.2V 輸入電壓:2.05 V ~ 6 V PWM 型:電壓模式 頻率 - 開關(guān):2MHz 電流 - 輸出:500mA 同步整流器:是 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:6-UFDFN 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:6-SON（1.45x1） 產(chǎn)品目錄頁面:1032 (CN2011-ZH PDF) 其它名稱:296-25628-2 |
| LT3470ETS8#TRMPBF | 制造商:Linear Technology 功能描述:DC/DC Converter IC 制造商:Linear Technology 功能描述:IC, BUCK REGULATOR, 8-TSOT-23 |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。