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参数资料
| 型号： | LTC3453EUF#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 9/12页 |
| 文件大小： | 0K |
| 描述： | IC LED DRIVER PHOTO FLASH 16-QFN |
| 标准包装： | 2,500 |
| 拓扑： | PWM，降压（降压），升压（升压） |
| 输出数： | 4 |
| 内部驱动器： | 是 |
| 类型 - 主要： | 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： | 16-WQFN 裸露焊盘 |
| 供应商设备封装： | 16-QFN（4x4） |
| 包装： | 带卷 (TR) |
| 工作温度： | -40°C ~ 85°C |
LTC3453
APPLICATIO S I FOR ATIO
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 2 for a list of component
suppliers.
Table 2. Capacitor Vendor Information
SUPPLIER WEB SITE
AVX www.avxcorp.com
Optional Schottky Diodes
Schottky diodes across the synchronous switches B and
D are not required, but provide a lower drop during the
break-before-make time (typically 20ns) of the NMOS to
PMOS transition, improving efficiency. Use a Schottky
diode such as an MBRM120T3 or equivalent. Do not use
ordinary rectifier diodes, since the slow recovery times
will compromise efficiency.
Sanyo
Taiyo Yuden
TDK
www.sanyovideo.com
www.t-yuden.com
www.component.tdk.com
Closing the Feedback Loop
The LTC3453 incorporates voltage mode PWM control.
The control to output gain varies with operation region
I OUT ( MAX ) ? ( V OUT IN ( MIN ) ) ? 100
% Ripple _ Boost = %
C OUT ? V OUT ? f
f FILTER _ POLE =
f FILTER _ ZERO =
2 ? π ? R ESR ? C OUT
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:
– V
2
% Ripple _ Buck = ( V IN ( MAX ) – V OUT ) ? 1 00 %
8 ? V IN ( MAX ) ? f 2 ? L ? C OUT
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
(Buck, Boost, Buck/Boost), but is usually no greater than
15. The output filter exhibits a double pole response
given by:
1
Hz
2 ? π ? L ? C OUT
where C OUT is the output filter capacitor.
The output filter zero is given by:
1
Hz
where R ESR is the capacitor equivalent series resistance.
A troublesome feature in Boost mode is the right-half
plane zero (RHP), and is given by:
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-
f RHPZ
=
2
V IN
2 ? π ? I OUT ? L ? V OUT
Hz
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-
tors or Sanyo POSCAP are recommended. For the white
LED application, a 4.7 μ F capacitor value is recommended.
The loop gain is typically rolled off before the RHP zero
frequency.
A simple Type I compensation network can be incorpo-
rated to stabilize the loop but at a cost of reduced band-
width and slower transient response. To ensure proper
phase margin, the loop requires to be crossed over a
decade before the LC double pole.
See Table 2 for a list of component suppliers.
3453fa
9
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC3454 | 制造商:LINER 制造商全称:Linear Technology 功能描述:1A Synchronous Buck-Boost High Current LED Driver |
| LTC3454EDD | 制造商:LINER 制造商全称:Linear Technology 功能描述:1A Synchronous Buck-Boost High Current LED Driver |
| LTC3454EDD#PBF | 功能描述:IC LED DRIVER PHOTO FLASH 10-DFN 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 |
| LTC3454EDD#TRPBF | 功能描述:IC LED DRIVER PHOTO FLASH 10-DFN 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 |
| LTC3454EDDPBF | 制造商:Linear Technology 功能描述:LED Driver 1A Buck-Boost 3.3/5V DFN10EP |
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