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参数资料
| 型号： | SP7652EB |
| 厂商： | Exar Corporation |
| 文件页数： | 9/15页 |
| 文件大小： | 0K |
| 描述： | EVAL BOARD FOR SP7652 |
| 标准包装： | 1 |
| 系列： | * |
S P 7 6 5 2
P o w e r b l o x T M
6 A 2 8 V 6 0 0 K H z S y n c h r o n o u s S t e p D o w n R e g u l a t o r
Standard 1% metal film resistors of surface
mount size 0603 are recommended.
Furthermore, one could select the value of the
R1 and R2 combination to meet the exact
output voltage setting by restricting R1
resistance range such that 50kΩ<R1<100kΩ
for overall system loop stability.
Where R1 = 68.1kΩ and for V OUT = 0.80V
setting, simply remove R2 from the board.
APPLICATION INFORMATION
I NDUCTOR S ELECTION
There are many factors to consider in selecting
the inductor including core material,
inductance vs. frequency, current handling
capability, efficiency, size and EMI. In a typical
SP7652 circuit, the inductor is chosen
primarily by operating frequency, saturation
current and DC resistance. Increasing the
inductor value will decrease output voltage
ripple, but degrade transient response. Low
inductor values provide the smallest size, but
cause large ripple currents, poor efficiency and
require more output capacitance to smooth
out the larger ripple current. The inductor
must be able to handle the peak current at the
switching frequency without saturating, and
the copper resistance in the winding should be
kept as low as possible to minimize resistive
power loss. A good compromise between size,
loss and cost is to set the inductor ripple
current to be within 20% to 40% of the
maximum output current.
The switching frequency and the inductor
operating point determine the inductor value
as follows:
where:
Fs = switching frequency
KrR = ratio of the AC inductor ripple current to
the maximum output current.
The peak to peak inductor ripple current is:
Once the required inductor value is selected,
the proper selection of core material is based
on peak inductor current and efficiency
requirements.
The core must be large enough not to saturate
at the peak inductor current
and provide low core loss at the high switching
frequency. Low cost powdered-iron cores are
inappropriate for 900kHz operation. Gapped
ferrite inductors are widely available for
consideration. Select devices that have
operating data shown up to 1 MHz. Ferrite
materials, on the other hand, are more
expensive and have an abrupt saturation
characteristic with the inductance dropping
sharply when the peak design current is
exceeded. Nevertheless, they are preferred at
high switching frequencies because they
present very low core loss and the design only
needs to prevent saturation. In general, ferrite
or molypermalloy materials are better choice
for all but the most cost sensitive applications.
O PTIMIZING E FFICIENCY
The power dissipated in the inductor is equal
to the sum of the core and copper losses. To
minimize copper losses, the winding resistance
needs to be minimized, but this usually comes
at the expense of a larger inductor. Core
losses have a more significant contribution at
low output current where the copper losses
are at a minimum, and can typically be
? 2012 Exar Corporation
9/15
Rev. 2.0.0
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相关代理商/技术参数 |
参数描述 |
|---|---|
| SP7652ER | 制造商:Rochester Electronics LLC 功能描述: 制造商:Exar Corporation 功能描述: |
| SP7652ER/TR | 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:Wide Input Voltage Range 6A, 600kHz, Buck Regulator |
| SP7652ERL | 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:Wide Input Voltage Range 6A, 600kHz, Buck Regulator |
| SP7652ER-L | 功能描述:电压模式 PWM 控制器 Buck Regulator RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel |
| SP7652ERL/TR | 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:Wide Input Voltage Range 6A, 600kHz, Buck Regulator |
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