参数资料
| 型号： | SC4519HSETRT |
| 厂商： | Semtech |
| 文件页数： | 8/14页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK 3A 8-SOIC |
| 标准包装： | 1 |
| 类型： | 降压（降压） |
| 输出数： | 1 |
| 输入电压： | 4.4 V ~ 24 V |
| PWM 型： | 电流模式 |
| 频率 - 开关： | 600kHz |
| 电流 - 输出： | 3A |
| 同步整流器： | 无 |
| 工作温度： | -40°C ~ 125°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 8-SOIC（0.154"，3.90mm Width）裸露焊盘 |
| 包装： | 标准包装 |
| 供应商设备封装： | 8-SO 裸露焊盘 |
| 产品目录页面： | 1358 (CN2011-ZH PDF) |
| 其它名称： | SC4519HSEDKR |
SC4519H
POWER MANAGEMENT
Application Information (Cont.)
The peak to peak inductor current is:
I p ? p = δ ? I OMAX
Maximum Load Current vs Input Voltage
L=10uH
After the required inductor value is selected, the proper
selection of the core material is based on the peak
I PEAK = I OMAX +
2.900
2.880
2.860
2.840
2.820
2.800
2.780
2.760
2.740
2.720
Vo=2.5V
Vo=3.3V
Vo=5V
inductor current and efficiency specifications. The core
must be able to handle the peak inductor current I PEAK
without saturation and produce low core loss during the
high frequency operation.
I p ? p
2
The power loss for the inductor includes its core loss and
2.700
4
6
8
10 12
Vi (V)
14
16
18
copper loss. If possible, the winding resistance should
be minimized to reduce inductor’s copper loss. The core
must be able to handle the peak inductor current I PEAK
without saturation and produce low core loss during the
Figure 2. Theoretical maximum load current curves
Inductor Selection
The factors for selecting the inductor include its cost,
efficiency, size and EMI. For a typical SC4519H
application, the inductor selection is mainly based on its
high frequency operation. The core loss can be found in
the manufacturer’s datasheet. The inductor’s copper loss
can be estimated as follows:
P COPPER = I 2 LRMS ? R WINDING
Where:
I LRMS is the RMS current in the inductor. This current can
be calculated as follows:
value, saturation current and DC resistance. Increasing
the inductor value will decrease the ripple level of the
output voltage while the output transient response will
I LRMS = I OMAX ? 1 +
1
12
? δ 2
V O ? (V I ? V O )
be degraded. Low value inductors offer small size and
fast transient responses while they allow large ripple
currents, poor efficiencies and require more output
capacitance for low output ripple. The inductor should
be able to handle the peak current without saturating
and its copper resistance in the winding should be as low
as possible to minimize its resistive power loss. A good
trade-off among its size, loss and cost is to set the
inductor ripple current to be within 15% to 30% of the
maximum output current.
The inductor value can be determined according to its
operating point under its continuous mode and the
switching frequency as follows:
L =
V I ? f s ? δ ? I OMAX
Where:
fs = switching frequency,
δ = ratio of the peak to peak inductor current to the
output load current and
V O = output voltage.
Output Capacitor Selection
Basically there are two major factors to consider in
selecting the type and quantity of the output capacitors.
The first one is the required ESR (Equivalent Series
Resistance) which should be low enough to reduce the
output voltage deviation during load changes. The second
one is the required capacitance, which should be high
enough to hold up the output voltage. Before the
SC4519H regulates the inductor current to a new value
during a load transient, the output capacitor delivers all
the additional current needed by the load. The ESR and
ESL of the output capacitor, the loop parasitic inductance
between the output capacitor and the load combined
with inductor ripple current are all major contributors to
the output voltage ripple. Surface mount ceramic
capacitors are recommended.
Input Capacitor Selection
The input capacitor selection is based on its ripple current
level, required capacitance and voltage rating. This
? 2007 Semtech Corp.
8
www.semtech.com
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| SC4524ASETRT | IC REG BUCK 2A 8SOIC |
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| SC4524DSETRT | IC REG BUCK ADJ 2A 8SOIC |
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相关代理商/技术参数 |
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| SC4519S.TRT | 制造商:SEMTECH 功能描述:I.C. |
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| SC451ITSTRT | 制造商:Semtech Corporation 功能描述: |
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