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参数资料
| 型号： | LTC3452EUF#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 11/16页 |
| 文件大小： | 0K |
| 描述： | IC LED DRIVER PHOTO FLASH 20-QFN |
| 标准包装： | 2,500 |
| 拓扑： | PWM，降压（降压），升压（升压） |
| 输出数： | 7 |
| 内部驱动器： | 是 |
| 类型 - 主要： | 背光，闪灯/白光 |
| 类型 - 次要： | 白色 LED |
| 频率： | 900kHz ~ 1.1MHz |
| 电源电压： | 2.7 V ~ 5.5 V |
| 输出电压： | 4.5V |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 20-WFQFN 裸露焊盘 |
| 供应商设备封装： | 20-QFN 裸露焊盘（4x4） |
| 包装： | 带卷 (TR) |
| 工作温度： | -40°C ~ 85°C |
LTC3452
APPLICATIO S I FOR ATIO
V IN ( MIN ) 2 ? ( V OUT V IN ( MIN ) ) ? 100 %
COMPONENT SELECTION
Inductor Selection
The high frequency operation of the LTC3452 allows the
use of small surface mount inductors. The inductor cur-
rent ripple is typically set to 20% to 40% of the maximum
average inductor current. For a given ripple the inductance
term in boost mode is:
–
L >
f ? I OUT ( MAX ) ? % Ripple ? V OUT 2
and in buck mode is:
Input Capacitor Selection
Since the V IN pin is the supply voltage for the IC it is
recommended to place at least a 2.2 μ F, low ESR bypass
capacitor to ground. See Table 3 for a list of component
suppliers.
Table 3. Capacitor Vendor Information
SUPPLIER WEB SITE
AVX www.avxcorp.com
Sanyo www.sanyovideo.com
Taiyo Yuden www.t-yuden.com
TDK www.component.tdk.com
L >
where:
V OUT ? ( V IN ( MAX ) – V OUT ) ? 100 %
f ? I OUT ( MAX ) ? % Rip p le ? V IN ( MAX )
Output Capacitor Selection
The bulk value of the capacitor is set to reduce the ripple
due to charge into the capacitor each cycle. The steady
state ripple due to charge is given by:
f = operating frequency, Hz
%Ripple = allowable inductor current ripple, %
V IN(MIN) = minimum input voltage, V
% Ripple _ Boost =
I OUT ( MAX ) ? ( V OUT – V IN ( MIN ) ) ? 100
C OUT ? V OUT 2 ? f
%
V IN(MAX) = maximum input voltage, V
V OUT = output voltage, V
I OUT(MAX) = maximum output load current
For high efficiency, choose an inductor with a high fre-
% Ripple _ Buck =
( V IN ( MAX ) – V OUT ) ? 1 00 %
8 ? V IN ( MAX ) ? f 2 ? L ? C OUT
quency core material, such as ferrite, to reduce core loses.
The inductor should have low ESR (equivalent series
resistance) to reduce the I 2 R losses, and must be able to
handle the peak inductor current without saturating. Molded
chokes or chip inductors usually do not have enough core
to support peak inductor currents >1A. To minimize radi-
ated noise, use a toroid, pot core or shielded bobbin
inductor. For the white LED application, a 4.7 μ H inductor
value is recommended. See Table 2 for a list of component
suppliers.
Table 2. Inductor Vendor Information
SUPPLIER WEB SITE
Coilcraft www.coilcraft.com
where C OUT = output filter capacitor, F
The output capacitance is usually many times larger in
order to handle the transient response of the converter.
For a rule of thumb, the ratio of the operating frequency to
the unity-gain bandwidth of the converter is the amount
the output capacitance will have to increase from the
above calculations in order to maintain the desired tran-
sient response.
The other component of ripple is due to the ESR (equiva-
lent series resistance) of the output capacitor. Low ESR
capacitors should be used to minimize output voltage
ripple. For surface mount applications, Taiyo Yuden, TDK,
AVX ceramic capacitors, AVX TPS series tantalum capaci-
Cooper/Coiltronics
Murata
Sumida
Vishay-Dale
www.cooperet.com
www.murata.com
www.japanlink.com/sumida
www.vishay.com
tors or Sanyo POSCAP are recommended. For the white
LED application, a 4.7 μ F capacitor value is recommended.
See Table 3 for a list of component suppliers.
3452f
11
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相关代理商/技术参数 |
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| LTC3453 | 制造商:LINER 制造商全称:Linear Technology 功能描述:700mA Low Noise High Current LED Charge Pump |
| LTC3453EUF | 制造商:Linear Technology 功能描述:LED DRVR 4Segment 3.3V/5V 16-Pin QFN EP |
| LTC3453EUF#PBF | 功能描述:IC LED DRIVER PHOTO FLASH 16-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - LED 驱动器 系列:- 标准包装:6,000 系列:- 恒定电流:- 恒定电压:- 拓扑:开路漏极，PWM 输出数:4 内部驱动器:是 类型 - 主要:LED 闪烁器 类型 - 次要:- 频率:400kHz 电源电压:2.3 V ~ 5.5 V 输出电压:- 安装类型:表面贴装 封装/外壳:8-VFDFN 裸露焊盘 供应商设备封装:8-HVSON 包装:带卷 (TR) 工作温度:-40°C ~ 85°C 其它名称:935286881118PCA9553TK/02-TPCA9553TK/02-T-ND |
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| LTC3454 | 制造商:LINER 制造商全称:Linear Technology 功能描述:1A Synchronous Buck-Boost High Current LED Driver |
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