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參數(shù)資料
| 型號： | LTC1174IN8#TRPBF |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | 1 A SWITCHING REGULATOR, 200 kHz SWITCHING FREQ-MAX, PDIP8 |
| 封裝： | 0.300 INCH, LEAD FREE, PLASTIC, DIP-8 |
| 文件頁數(shù)： | 19/20頁 |
| 文件大?。?/td> | 251K |
| 代理商： | LTC1174IN8#TRPBF |
8
LTC1174
LTC1174-3.3/LTC1174-5
1174fe
Inductor Core Selection
With the value of L selected, the type of inductor must be
chosen. Basically there are two kinds of losses in an
inductor, core and copper
Core losses are dependent on the peak-to-peak ripple
current and the core material. However it is independent of
the physical size of the core. By increasing the inductance
the inductor’s peak-to-peak ripple current will decrease,
therefore reducing core loss. Utilizing low core loss mate-
rial, such as molypermalloy or Kool M
will allow users to
concentrate on reducing copper loss and preventing satu-
ration. Figure 1 shows the effect of different core material on
the efficiency of the LTC1174. The CTX core is Kool M
and
the CTXP core is powdered iron (material 52).
Although higher inductance reduces core loss, it increases
copper loss as it requires more windings. When space is not
Figure 1. Efficiency Using Different Types of
Inductor Core Material
APPLICATIO S I FOR ATIO
WU
UU
LOAD CURRENT (mA)
1
EFFICIENCY
(%)
10
100
500
100
90
80
70
60
50
VIN = 5V
VOUT = 3.3V
IPGM = VIN
CTX50-4
CTX50-4P
1174 F01
LOAD CURRENT (mA)
1
EFFICIENCY
(%)
10
100
500
100
90
80
70
60
50
VIN = 5V
VOUT = 3.3V
IPGM = VIN
CTX100-4
CTX100-4P
a premium larger gauge wire can be used to reduce the wire
resistance. This also prevents excessive heat dissipation.
CIN
In continuous mode the source current of the P-channel
MOSFET is a square wave of duty cycle VOUT/VIN.Toprevent
large voltage transients, a low ESR input capacitor sized for
the maximum RMS current must be used. The CIN RMS
current is given by:
I
IV
V
A
RMS
OUT
IN
OUT
IN
RMS
≈
()
[]
()
12
/
This formula has a maximum at VIN = 2VOUT, where IRMS =
IOUT/2.Thissimpleworstcaseiscommonlyusedfordesign
because even significant deviations do not offer much relief.
Note that ripple current directly affects capacitor’s lifetime.
DO NOT UNDERSPECIFY THIS COMPONENT. An additional
0.1
F ceramic capacitor is also required on VIN for high
frequency decoupling.
COUT
To avoid overheating, the output capacitor must be sized to
handle the ripple current generated by the inductor. The
worst case RMS ripple current in the output capacitor is
given by:
I
A
mA
RMS
PEAK
RMS
≈
()
=
2
170
or 300mA
Although the output voltage ripple is determined by the
hysteresis of the voltage comparator, ESR of the output
capacitor is also a concern. Too high of an ESR will create
a higher ripple output voltage and at the same time cause the
LTC1174 to sleep less often. This will affect the efficiency of
the LTC1174. For a given technology, ESR is a direct
function of the volume of the capacitor. Several small-sized
capacitors can also be paralleled to obtain the same ESR as
one large can. Manufacturers such as Nichicon, Chemicon
and Sprague should be considered for high performance
capacitors. The OS-CON semiconductor dielectric capaci-
tor available from Sanyo has the lowest ESR for its size, at
a higher price.
相關(guān)PDF資料 |
PDF描述 |
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| LTC1174CN8#TRPBF | 1 A SWITCHING REGULATOR, 200 kHz SWITCHING FREQ-MAX, PDIP8 |
| LTC1174CN8-5#TRPBF | 1 A SWITCHING REGULATOR, 200 kHz SWITCHING FREQ-MAX, PDIP8 |
| LTC1174CN8-5#TR | 1 A SWITCHING REGULATOR, 200 kHz SWITCHING FREQ-MAX, PDIP8 |
| LTC1174HVCS8#TR-5 | SWITCHING REGULATOR, 200 kHz SWITCHING FREQ-MAX, PDSO8 |
| LTC1174CS8#TR-5 | SWITCHING REGULATOR, 200 kHz SWITCHING FREQ-MAX, PDSO8 |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LTC1174IS8 | 功能描述:IC REG BUCK INV ADJ 1A 8SOIC 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 |
| LTC1174IS8#PBF | 功能描述:IC REG BUCK INV ADJ 1A 8SOIC 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: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 |
| LTC1174IS8#TR | 功能描述:IC REG BUCK INV ADJ 1A 8SOIC 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 |
| LTC1174IS8#TRPBF | 功能描述:IC REG BUCK INV ADJ 1A 8SOIC 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: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 |
| LTC1177-12 | 制造商:LINER 制造商全稱:Linear Technology 功能描述:Isolated MOSFET Drivers |
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