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| 型号： | IR3811MTRPBF |
| 厂商： | International Rectifier |
| 文件页数： | 12/21页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK SYNC ADJ 7A 15QFN |
| 产品培训模块： | SupIRBuck™ Integrated Point-of-Load Regulators SupIRBuck? Family and POL Design Tools Overview |
| 产品变化通告： | (EP) Parts Discontinuation 25/May/2012 |
| 标准包装： | 1 |
| 系列： | SupIRBuck™ |
| 类型： | 降压（降压） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 0.6 V ~ 12 V |
| 输入电压： | 2.5 V ~ 21 V |
| PWM 型： | 电压模式 |
| 频率 - 开关： | 600kHz |
| 电流 - 输出： | 7A |
| 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： | 15-PowerVQFN |
| 包装： | 标准包装 |
| 供应商设备封装： | PQFN（5x6） |
| 产品目录页面： | 1384 (CN2011-ZH PDF) |
| 其它名称： | IR3811MTRPBFDKR |
PD-60334
IR3811MPbF
Input Capacitor Selection
The input filter capacitor should be selected
based on how much ripple the supply can
tolerate on the DC input line. The ripple current
generated during the on time of upper MOSFET
should be provided by the input capacitor. The
RMS value of this ripple is expressed by:
If Δ i ≈ 30 %( I o , ) then the output inductor will be:
L = 0.6uH
Delta MLP-104 series provides a range of
inductors in different values, and small size
suitable for this application.
D = o
I RMS = I o ? D ? ( 1 ? D )
Where:
D is the Duty Cycle
--( 7 )
V
V in
Output Capacitor Selection
The voltage ripple and transient requirements
determine the output capacitors’ type and values.
The criteria is normally based on the value of the
Effective Series Resistance (ESR). However the
I RMS is the RMS value of the input capacitor
current.
Io is the output current.
For Io=7A and D=0.0625, the I RMS =1.69A.
Ceramic capacitors are recommended due to
actual capacitance value and the Equivalent
Series Inductance (ESL) are other contributing
components. These components can be
described as:
Δ V o = Δ V o ( ESR ) + Δ V o ( ESL ) + Δ V o ( C )
Δ V o ( ESL ) = ?
? V in ?
their peak current capabilities. They also feature
low ESR and ESL at higher frequency which
results in better efficiency,
Use 3x10uF, 16V ceramic capacitors from
Panasonic.
Δ V o ( ESR ) = Δ I L * ESR
? * ESL
? L ?
- -(9)
Inductor Selection
The inductor is selected based on output power,
operating frequency and efficiency requirements.
Δ V o ( C ) =
Δ I L
8 * C o * F s
; Δ t = D ?
V in ? V o = L ?
A low inductor value causes a large ripple
current, resulting in the smaller size, faster
response to a load transient but poor efficiency
and high output noise. Generally, the selection of
the inductor value can be reduced to the desired
maximum ripple current in the inductor ( Δ i ) . The
optimum point is usually found between 20% and
50% ripple of the output current.
For the buck converter, the inductor value for the
desired operating ripple current can be
determined using the following:
s
Δ i 1
Δ t F
Δ V o = Output voltage ripple
Δ I L = Inductor ripple current
Since the output capacitor has a major role in the
overall performance of converter and determine
the result of transient response, selection of the
capacitor is critical. The IR3811 can perform well
with all types of capacitors.
As a rule the capacitor must have low enough
ESR to meet output ripple and load transient
requirements, yet have high enough ESR to
satisfy stability requirements.
L = ( V in ? V o ) ?
Where:
V o
V in ? Δ i * F s
--( 8 )
The goal for this design is to meet the voltage
ripple requirement in the smallest possible
capacitor size. Therefore, a ceramic capacitor is
selected due to its low ESR and small size. Six of
V in = Maximum input voltage
V o = Output Voltage
Δ i = Inductor ripple current
F s = Switching frequency
Δ t = Turn on time
D = Duty cycle
10/04/08
the Panasonic ECJ2FB0J226M (22uF, 6.3V, X5R
and EIA 0805 case size) are a good choice.
In the case of tantalum or low ESR electrolytic
capacitors, the ESR dominates the output
voltage ripple, equation (9) can be used to
calculate the required ESR for the specific
voltage ripple.
12
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相关代理商/技术参数 |
参数描述 |
|---|---|
| IR3812MPBF | 制造商:International Rectifier 功能描述: |
| IR3812MPBF_08 | 制造商:IRF 制造商全称:International Rectifier 功能描述:HIGHLY INTEGRATED 4A WIDE-INPUT VOLTAGE, SYNCHRONOUS BUCK REGULATOR |
| IR3812MTR1PBF | 功能描述:直流/直流开关调节器 4A SupIRBuck Reg 600kHz, 2.5-21V in RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| IR3812MTRPBF | 功能描述:直流/直流开关调节器 4A SupIRBuck Reg 600kHz, 2.5-21V in RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| IR3820AMPBF | 制造商:International Rectifier 功能描述:Conv DC-DC Single Step Down 2.5V to 21V 15-Pin Power QFN EP |
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