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参数资料
| 型号： | LTC3544BEUD#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 10/18页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK SYNC ADJ QUAD 16QFN |
| 标准包装： | 2,500 |
| 类型： | 降压（降压） |
| 输出类型： | 可调式 |
| 输出数： | 4 |
| 输出电压： | 0.8 V ~ 5.5 V |
| 输入电压： | 2.25 V ~ 5.5 V |
| PWM 型： | 电流模式 |
| 频率 - 开关： | 2.25MHz |
| 电流 - 输出： | 100mA，200mA（2），300mA |
| 同步整流器： | 是 |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 16-WFQFN 裸露焊盘 |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | 16-QFN-EP（3x3） |
LTC3544B
APPLICATIONS INFORMATION
V OUT ? 1 – OUT ?
Δ I L =
1 ? V ?
( ? )( L )
V OUT ( V IN – V OUT )
V IN
The basic LTC3544B application circuit is shown on the
first page of this data sheet. External component selec-
tion is driven by the load requirement and begins with the
selection of L followed by C IN and C OUT .
Inductor Selection
For most applications, the value of the inductor will fall in
the range of 1μH to 10μH. Its value is chosen based on the
desired ripple current. Large inductor values lower ripple
current and small inductor values result in higher ripple
currents. Higher V IN or V OUT also increases the ripple
current as shown in Equation 1. A reasonable starting
point for setting ripple current for the 300mA regulator is
Δ I L = 120mA (40% of 300mA).
(1)
? V IN ?
The DC current rating of the inductor should be at least equal
to the maximum load current plus half the ripple current
to prevent core saturation. Thus, a 360mA rated inductor
should be enough for most applications (300mA + 60mA).
For better efficiency, choose a low DCR inductor.
Inductor Core Selection
Different core materials and shapes will change the
size/current and price/current relationship of an induc-
tor. Toroid or shielded pot cores in ferrite or permalloy
materials are small and don’t radiate much energy, but
generally cost more than powdered iron core inductors
with similar electrical characteristics. The choice of which
style inductor to use often depends more on the price vs.
size requirements and any radiated field/EMI requirements
than on what the LTC3544B requires to operate. Table 1
shows typical surface mount inductors that work well in
LTC3544B applications.
Table 1. Representative Surface Mount Inductors
VALUE DCR MAX DC
PART NUMBER (μH) ( Ω MAX) CURRENT (A) W × L × H (mm 3 )
Sumida 10 0.47 0.48 3.0 × 2.8 × 1.0
CDH2D09B 6.4 0.32 0.6
4.7 0.218 0.7
3.3 0.15 0.85
Wurth 10 0.50 0.50 2.8 × 2.8 × 1.35
TPC744029 6.8 0.38 0.65
4.7 0.210 0.80
3.3 0.155 0.95
TDK 10 0.67 0.49 2.8 × 2.6 × 1.0
VLF3010AT 6.8 0.39 0.61
4.7 0.28 0.70
3.3 0.17 0.87
C IN and C OUT Selection
In continuous mode, a worst-case estimate for the input
current ripple can be determined my assuming that the
source current of the top MOSFET is a square wave of duty
cycle V OUT /V IN , and amplitude I OUT(MAX) . To prevent large
voltage transients, a low ESR input capacitor sized for the
maximum RMS current must be used. The maximum RMS
capacitor current is given by:
I RMS ? I OUT ( MAX )
This formula has a maximum at V IN = 2V OUT , where I RMS
= I OUT /2. This simple worst-case condition is commonly
used for design. Note that the capacitor manufacturer’s
ripple current ratings are often based on 2000 hours of
life (non-ceramic capacitors). This makes it advisable to
further de-rate the capacitor, or choose a capacitor rated
at a higher temperature than required. Always consult the
manufacturer if there is any question.
The selection of C OUT is driven by the required effective
series resistance (ESR). Typically, once the ESR require-
ment for C OUT has been met, the RMS current rating
3544bfb
0
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相关代理商/技术参数 |
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|---|---|
| LTC3544EUD | 制造商:LINER 制造商全称:Linear Technology 功能描述:Quad Synchronous Step-Down Regulator: 2.25MHz, 300mA, 200mA, 200mA, 100mA |
| LTC3544EUD#PBF | 功能描述:IC REG BUCK SYNC ADJ QUAD 16QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 标准包装:250 系列:- 类型:降压（降压） 输出类型:固定 输出数:1 输出电压:1.2V 输入电压:2.05 V ~ 6 V PWM 型:电压模式 频率 - 开关:2MHz 电流 - 输出:500mA 同步整流器:是 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:6-UFDFN 包装:带卷 (TR) 供应商设备封装:6-SON（1.45x1） 产品目录页面:1032 (CN2011-ZH PDF) 其它名称:296-25628-2 |
| LTC3544EUD#TRPBF | 功能描述:IC REG BUCK SYNC ADJ QUAD 16QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 标准包装:2,500 系列:- 类型:降压（降压） 输出类型:固定 输出数:1 输出电压:1.2V，1.5V，1.8V，2.5V 输入电压:2.7 V ~ 20 V PWM 型:- 频率 - 开关:- 电流 - 输出:50mA 同步整流器:是 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:10-TFSOP，10-MSOP（0.118"，3.00mm 宽）裸露焊盘 包装:带卷 (TR) 供应商设备封装:10-MSOP 裸露焊盘 |
| LTC3544EUDPBF | 制造商:Linear Technology 功能描述:2.25MHz Sync Step-Down Converter LTC3544 |
| LTC3544EUD-PBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:Quad Synchronous Step-Down Regulator: 2.25MHz, 300mA, 200mA, 200mA, 100mA |
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