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參數(shù)資料
| 型號(hào)： | LT1173 |
| 廠商： | Linear Technology Corporation |
| 英文描述： | Micropower DC/DC Converter Adjustable and Fixed 5V, 12V(微功耗，固定輸出12V或5V及可調(diào)輸出，DC/DC變換器（工作于步升和步降兩種模式）) |
| 中文描述： | 微功率DC / DC轉(zhuǎn)換可調(diào)和固定5V，12V的（微功耗，固定輸出12V的或5V的及可調(diào)輸出，直流/直流變換器（工作于步升和步降兩種模式）） |
| 文件頁(yè)數(shù)： | 6/16頁(yè) |
| 文件大?。?/td> | 256K |
| 代理商： | LT1173 |
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LT1173
6
U
S
A
O
PPLICATI
U
U
LT1173 TA06
+
–
SET
V
+12V
+
μ
1 F*
μ
1000 F
100
V1
V2
LTC1050
1M
LT1173
CIRCUIT
*NON-POLARIZED
Figure 1. Test Circuit Measures No Load Quiescent Current of
LT1073 Converter
Inductor Selection
A DC-DC converter operates by storing energy as mag-
netic flux in an inductor core, and then switching this
energy into the load. Since it is flux, not charge, that is
stored, the output voltage can be higher, lower, or oppo-
site in polarity to the input voltage by choosing an
appropriate switching topology. To operate as an efficient
energy transfer element, the inductor must fulfill three
requirements. First, the inductance must be low enough
for the inductor to store adequate energy under the worst
case condition of minimum input voltage and switch ON
time. The inductance must also be high enough so that
maximum current ratings of the LT1173 and inductor are
not exceeded at the other worst case condition of maxi-
mum input voltage and ON time. Additionally, the inductor
core must be able to store the required flux; i.e., it must not
saturate At power levels generally encountered with
LT1173 based designs, small axial leaded units with
saturation current ratings in the 300mA to 1A range
(depending on application) are adequate. Lastly, the in-
ductor must have sufficiently low DC resistance so that
excessive power is not lost as heat in the windings. An
additional consideration is Electro-Magnetic Interference
(EMI). Toroid and pot core type inductors are recom-
mended in applications where EMI must be kept to a
minimum; for example, where there are sensitive analog
circuitry or transducers nearby. Rod core types are a less
expensive choice where EMI is not a problem.
Specifying a proper inductor for an application requires
first establishing minimum and maximum input voltage,
output voltage, and output current. In a step-up converter,
the inductive events add to the input voltage to produce the
output voltage. Power required from the inductor is deter-
mined by
P
L
= (V
OUT
+ V
D
– V
IN
) (I
OUT
)
(02)
where V
D
is the diode drop (0.5V for a 1N5818 Schottky).
Energy required by the inductor per cycle must be equal or
greater than
P
F
L
OSC
03
( )
in order for the converter to regulate the output.
When the switch is closed, current in the inductor builds
according to
I
t
V
R
e
L
IN
'
L
( )
=
( )
–
–R t
1
04
where R' is the sum of the switch equivalent resistance
(0.8
typical at 25
°
C) and the inductor DC resistance.
When the drop across the switch is small compared to V
IN
,
the simple lossless equation
I
t
V
L
t
L
IN
( )
=
( )
05
can be used. These equations assume that at t = 0,
inductor current is zero. This situation is called “discon-
tinuous mode operation” in switching regulator parlance.
Setting “t” to the switch ON time from the LT1173 speci-
fication table (typically 23
μ
s) will yield i
PEAK
for a specific
“L” and V
IN
. Once i
PEAK
is known, energy in the inductor at
the end of the switch ON time can be calculated as
E
Li
L
PEAK
=
( )
1
2
06
2
E
L
must be greater than P
L
/F
OSC
for the converter to deliver
the required power. For best efficiency i
PEAK
should be
kept to 1A or less. Higher switch currents will cause
excessive drop across the switch resulting in reduced
efficiency. In general, switch current should be held to as
low a value as possible in order to keep switch, diode and
inductor losses at a minimum.
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LT1173-12 | 制造商:LINER 制造商全稱:Linear Technology 功能描述:Micropower DC/DC Converter Adjustable and Fixed 5V, 12V |
| LT1173-5 | 制造商:LINER 制造商全稱:Linear Technology 功能描述:Micropower DC/DC Converter Adjustable and Fixed 5V, 12V |
| LT1173CN8 | 功能描述:IC REG BUCK BST INV ADJ .4A 8DIP RoHS:否 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(wú) 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 |
| LT1173CN8#PBF | 功能描述:IC REG BUCK BST INV ADJ .4A 8DIP 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:- 產(chǎn)品培訓(xùn)模塊:MIC23xxx HyperLight Load™ Regulators 標(biāo)準(zhǔn)包裝:5,000 系列:HyperLight Load® 類型:降壓（降壓） 輸出類型:固定 輸出數(shù):1 輸出電壓:1.8V 輸入電壓:2.7 V ~ 5.5 V PWM 型:混合物 頻率 - 開關(guān):4MHz 電流 - 輸出:2A 同步整流器:是 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:8-VFDFN 裸露焊盤，8-MLF? 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:8-MLF?（2x2） 產(chǎn)品目錄頁(yè)面:1094 (CN2011-ZH PDF) 其它名稱:576-3303-2 |
| LT1173CN8-12 | 功能描述:IC REG BUCK BST INV 12V .4A 8DIP RoHS:否 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:降壓（降壓） 輸出類型:固定 輸出數(shù):1 輸出電壓:1.2V，1.5V，1.8V，2.5V 輸入電壓:2.7 V ~ 20 V PWM 型:- 頻率 - 開關(guān):- 電流 - 輸出:50mA 同步整流器:是 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:10-TFSOP，10-MSOP（0.118"，3.00mm 寬）裸露焊盤 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:10-MSOP 裸露焊盤 |
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