- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄44983 > LT1933HDCB (LINEAR TECHNOLOGY CORP) 1.05 A SWITCHING REGULATOR, 600 kHz SWITCHING FREQ-MAX, PDSO6 PDF資料下載
參數(shù)資料
| 型號(hào)： | LT1933HDCB |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | 1.05 A SWITCHING REGULATOR, 600 kHz SWITCHING FREQ-MAX, PDSO6 |
| 封裝： | 2 X 3 MM, 0.75 MM HEIGHT, PLASTIC, MO-229, DFN-6 |
| 文件頁(yè)數(shù)： | 18/20頁(yè) |
| 文件大小： | 357K |
| 代理商： | LT1933HDCB |
第1頁(yè)第2頁(yè)第3頁(yè)第4頁(yè)第5頁(yè)第6頁(yè)第7頁(yè)第8頁(yè)第9頁(yè)第10頁(yè)第11頁(yè)第12頁(yè)第13頁(yè)第14頁(yè)第15頁(yè)第16頁(yè)第17頁(yè)當(dāng)前第18頁(yè)第19頁(yè)第20頁(yè)
LT1933
7
1933fe
OPERATION (Refer to Block Diagram)
The LT1933 is a constant frequency, current mode step
down regulator. A 500kHz oscillator enables an RS ip-
op, turning on the internal 750mA power switch Q1. An
amplier and comparator monitor the current owing
between the VIN and SW pins, turning the switch off when
this current reaches a level determined by the voltage at
VC. An error amplier measures the output voltage through
an external resistor divider tied to the FB pin and servos
the VC node. If the error amplier’s output increases, more
current is delivered to the output; if it decreases, less cur-
rent is delivered. An active clamp (not shown) on the VC
node provides current limit. The VC node is also clamped
to the voltage on the SHDN pin; soft-start is implemented
by generating a voltage ramp at the SHDN pin using an
external resistor and capacitor.
An internal regulator provides power to the control cir-
cuitry. This regulator includes an undervoltage lockout
to prevent switching when VIN is less than ~3.35V. The
SHDN pin is used to place the LT1933 in shutdown, dis-
connecting the output and reducing the input current to
less than 2μA.
The switch driver operates from either the input or from
the BOOST pin. An external capacitor and diode are 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 efcient opera-
tion.
The oscillator reduces the LT1933’s operating frequency
when the voltage at the FB pin is low. This frequency
foldback helps to control the output current during startup
and overload.
APPLICATIONS INFORMATION
FB Resistor Network
The output voltage is programmed with a resistor divider
between the output and the FB pin. Choose the 1% resis-
tors according to:
R1 = R2(VOUT/1.245 – 1)
R2 should be 20k or less to avoid bias current errors.
Reference designators refer to the Block Diagram.
Input Voltage Range
The input voltage range for LT1933 applications depends
on the output voltage and on the absolute maximum rat-
ings of the VIN and BOOST pins.
The minimum input voltage is determined by either the
LT1933’s minimum operating voltage of ~3.35V, or by its
maximum duty cycle. The duty cycle is the fraction of
time that the internal switch is on and is determined by
the input and output voltages:
DC = (VOUT + VD)/(VIN – VSW + VD)
where VD is the forward voltage drop of the catch diode
(~0.4V) and VSW is the voltage drop of the internal switch
(~0.4V at maximum load). This leads to a minimum input
voltage of:
VIN(MIN) = (VOUT + VD)/DCMAX – VD + VSW
with DCMAX = 0.88
The maximum input voltage is determined by the absolute
maximum ratings of the VIN and BOOST pins and by the
minimum duty cycle DCMIN = 0.08 (corresponding to a
minimum on time of 130ns):
VIN(MAX) = (VOUT + VD)/DCMIN – VD + VSW
Note that this is a restriction on the operating input voltage;
the circuit will tolerate transient inputs up to the absolute
maximum ratings of the VIN and BOOST pins.
Inductor Selection and Maximum Output Current
A good rst choice for the inductor value is:
L = 5 (VOUT + VD)
where VD is the voltage drop of the catch diode (~0.4V)
and L is in μH. With this value the maximum load current
will be above 500mA. The inductor’s RMS current rating
must be greater than your maximum load current and its
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LT1933HS6 | 1.05 A SWITCHING REGULATOR, 600 kHz SWITCHING FREQ-MAX, PDSO6 |
| LT1933IDCB#PBF | 1.05 A SWITCHING REGULATOR, 600 kHz SWITCHING FREQ-MAX, PDSO6 |
| LT1933IS6#PBF | 1.05 A SWITCHING REGULATOR, 600 kHz SWITCHING FREQ-MAX, PDSO6 |
| LT1934IS6#PBF | 0.49 A SWITCHING REGULATOR, PDSO6 |
| LT1934ES6-1#PBF | 0.16 A SWITCHING REGULATOR, PDSO6 |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LT1933HDCB#PBF | 制造商:Linear Technology 功能描述: |
| LT1933HDCB#TRMPBF | 功能描述:IC REG BUCK ADJ 0.6A 6DFN 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(biāo)準(zhǔn)包裝:2,500 系列:- 類型:升壓（升壓） 輸出類型:可調(diào)式 輸出數(shù):1 輸出電壓:1.24 V ~ 30 V 輸入電壓:1.5 V ~ 12 V PWM 型:電流模式，混合 頻率 - 開關(guān):600kHz 電流 - 輸出:500mA 同步整流器:無 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:8-SOIC（0.154"，3.90mm 寬） 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:8-SOIC |
| LT1933HDCB#TRPBF | 功能描述:IC REG BUCK ADJ 0.6A 6DFN 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(biāo)準(zhǔn)包裝:2,500 系列:- 類型:升壓（升壓） 輸出類型:可調(diào)式 輸出數(shù):1 輸出電壓:1.24 V ~ 30 V 輸入電壓:1.5 V ~ 12 V PWM 型:電流模式，混合 頻率 - 開關(guān):600kHz 電流 - 輸出:500mA 同步整流器:無 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:8-SOIC（0.154"，3.90mm 寬） 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:8-SOIC |
| LT1933HDCB-PBF | 制造商:LINER 制造商全稱:Linear Technology 功能描述:600mA, 500kHz Step-Down Switching Regulator in SOT-23 and DFN Packages |
| LT1933HDCB-TR | 制造商:LINER 制造商全稱:Linear Technology 功能描述:600mA, 500kHz Step-Down Switching Regulator in SOT-23 and DFN Packages |
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。