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参数资料
| 型号： | LTC3545IUD-1#PBF |
| 厂商： | Linear Technology |
| 文件页数： | 13/20页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK SYNC ADJ 0.8A 16QFN |
| 标准包装： | 121 |
| 类型： | 降压（降压） |
| 输出类型： | 可调式 |
| 输出数： | 3 |
| 输出电压： | 0.6 V ~ 5.5 V |
| 输入电压： | 2.25 V ~ 5.5 V |
| PWM 型： | 电流模式，混合 |
| 频率 - 开关： | 2.25MHz |
| 电流 - 输出： | 800mA |
| 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： | 16-WFQFN 裸露焊盘 |
| 包装： | 管件 |
| 供应商设备封装： | 16-QFN-EP（3x3） |
LTC3545/LTC3545-1
APPLICATIONS INFORMATION
Δ V OUT L ? ESR +
? Δ I
V OUT = 0 . 6 V ? 1 +
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
generally far exceeds the I RIPPLE(P-P) requirement. The
output ripple Δ V OUT is determined by:
? 1 ?
?
? 8 ? ? ? C OUT ?
where f = operating frequency, C OUT = output capacitance
and Δ I L = ripple current in the inductor. For a ?xed output
Output Voltage Programming
The output voltage is set by tying V FB to a resistive divider
according to the following formula:
? R2 ?
?
? R 1 ?
The external resistive divider is connected to the output
allowing remote voltage sensing as shown in Figure 2.
0.6V ≤ V OUT ≤ 5.5V
voltage, the output ripple is highest at maximum input
voltage since Δ I L increases with input voltage.
V FB
R2
Using Ceramic Input and Output Capacitors
LTC3545
GND
R1
Higher value, lower cost, ceramic capacitors are now
widely available in smaller case sizes. Their high ripple
current, high voltage rating and low ESR make them
ideal for switching regulator applications. Because the
LTC3545/LTC3545-1’s control loop does not depend on
the output capacitor’s ESR for stable operation, ceramic
capacitors can be used freely to achieve very low output
ripple and small circuit size.
However, care must be taken when ceramic capacitors are
used at the input and the output. When a ceramic capacitor
is used at the input and the power is supplied by a wall
adapter through long wires, a load step at the output can
induce ringing at the input, V IN . At best, this ringing can
couple to the output and be mistaken as loop instability. At
worst, a sudden inrush of current through the long wires
can potentially cause a voltage spike at V IN , large enough
to damage the part.
When choosing the input and output ceramic capacitors,
choose the X5R or X7R dielectric formulations. These
dielectrics have the best temperature and voltage charac-
teristics of all the ceramics for a given value and size.
3545 F02
Figure 2. Setting the LTC3545 Output Voltage
Ef?ciency Considerations
The ef?ciency of a switching regulator is equal to the output
power divided by the input power times 100%. It is often
useful to analyze individual losses to determine what is
limiting the ef?ciency and which change would produce
the most improvement. Ef?ciency can be expressed as:
Ef?ciency = 100% – (L1 + L2 + L3 + ...) where L1, L2, etc.
are the individual losses as a percentage of input power.
Although all dissipative elements in the circuit produce
losses, two main sources usually account for most of the
losses in LTC3545/LTC3545-1 circuits: V IN quiescent cur-
rent and I 2 R losses. V IN quiescent current loss dominates
the ef?ciency loss at low load currents, whereas the I 2 R
loss dominates the ef?ciency loss at medium to high load
currents. In a typical ef?ciency plot, the ef?ciency curve at
very low load currents can be misleading since the actual
power lost is of little consequence as illustrated on the
front page of the data sheet.
35451fb
13
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC3545IUD-1-TRPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:Triple 800mA Synchronous Step-Down Regulator-2.25MHz |
| LTC3545IUD-PBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:Triple 800mA Synchronous Step-Down Regulator-2.25MHz |
| LTC3545IUD-TRPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:Triple 800mA Synchronous Step-Down Regulator-2.25MHz |
| LTC3546 | 制造商:LINER 制造商全称:Linear Technology 功能描述:Dual Synchronous, 3A/1A or 2A/2A Confi gurable Step-Down DC/DC Regulator |
| LTC3546EFE#PBF | 功能描述:IC REG BUCK SYNC ADJ DL 28TSSOP 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 |
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