参数资料
| 型号： | SC173MLTRT |
| 厂商： | Semtech |
| 文件页数： | 15/27页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK SYNC ADJ 3A 10MLPD |
| 产品培训模块： | Power Supplies 101 |
| 标准包装： | 1 |
| 系列： | EcoSpeed® |
| 类型： | 降压（降压） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 0.75 V ~ 5.23 V |
| 输入电压： | 3 V ~ 5.5 V |
| 频率 - 开关： | 200kHz ~ 1MHz |
| 电流 - 输出： | 3A |
| 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： | 10-VFDFN 裸露焊盘 |
| 包装： | 标准包装 |
| 供应商设备封装： | 10-MLPD（3x3） |
| 其它名称： | SC173MLDKR |
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SC173
Applications Information (continued)
setting the frequency) using the following equation.
below 2.7V.
Design Procedure
When designing a switch mode supply the input voltage
R TON =
1
25pF ? f SW
range, load current, switching frequency, and inductor
ripple current must be specified.
The maximum input voltage (V INMAX ) is the highest speci-
fied input voltage. The minimum input voltage ( V INMIN ) is
determined by the lowest input voltage after evaluating
the voltage drops due to connectors, fuses, switches, and
PCB traces.
The following parameters define the design.
Calculating R TON results in the following solution.
R TON =50k W, we use R TON =49.9k W in real application.
Inductor Selection
In order to determine the inductance, the ripple cur-
rent must first be defined. Low inductor values result in
smaller size but create higher ripple current which can
reduce efficiency. Higher inductor values will reduce the
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Nominal output voltage (V OUT )
Static or DC output tolerance
Transient response
Maximum load current (I OUT )
ripple current/voltage and for a given DC resistance are
more efficient. However, larger inductance translates di-
rectly into larger packages and higher cost. Cost, size,
output ripple, and efficiency are all used in the selection
process.
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There are two values of load current to evaluate — con-
tinuous load current and peak load current. Continuous
load current relates to thermal stresses which drive the
selection of the inductor and input capacitors. Peak load
current determines instantaneous component stresses and
filtering requirements such as inductor saturation, output
capacitors, and design of the current limit circuit.
The following values are used in this design.
V IN = 5V + 10%
V OUT = 1.0V + 4%
f SW = 800kHz
Load = 3A maximum
Frequency Selection
Selection of the switching frequency requires making a
trade-off between the size and cost of the external filter
The ripple current will also set the boundary for power-
save operation. The switching will typically enter power-
save mode when the load current decreases to 1/2 of the
ripple current. For example, if ripple current is 3A then
power-save operation will typically start for loads less
than 1.5A. If ripple current is set at 40% of maximum load
current, then power-save will start for loads less than 20%
of maximum current.
The inductor value is typically selected to provide a rip-
ple current that is between 25% to 50% of the maximum
load current. This provides an optimal trade-off between
cost, efficiency, and transient performance.
During the DH on-time, voltage across the inductor is
(V IN - V OUT ). The equation for determining inductance is
shown next.
components (inductor and output capacitor) and the
power conversion efficiency.
The desired switching frequency is 800kHz which results
T ON =
V OUT
V INMAX ? f SW
from using components selected for optimum size and
cost .
A resistor (R TON ) is used to program the on-time (indirectly
? 2010 Semtech Corporation
L =
(V IN - V OUT ) × T ON
I RIPPLE
15
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相关代理商/技术参数 |
参数描述 |
|---|---|
| SC174 | 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:4A EcoSpeedTM Synchronous Step-Down Regulator with Optional Ultrasonic Power Save |
| SC1743 | 制造商:ROEBUCK 功能描述:HAND STRETCH FILM |
| SC174EVB | 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:4A EcoSpeedTM Synchronous Step-Down Regulator with Optional Ultrasonic Power Save |
| SC174ML.TRT | 制造商:Semtech Corporation 功能描述: |
| SC174MLTRT | 功能描述:IC REG BUCK SYNC ADJ 4A 10MLPD RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:EcoSpeed® 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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