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参数资料
| 型号： | SP7651ER-L/TR |
| 厂商： | Exar Corporation |
| 文件页数： | 8/15页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK SYNC ADJ 3A 26DFN |
| 标准包装： | 3,000 |
| 系列： | Power Blox™ |
| 类型： | 降压（降压） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 0.8 V ~ 19 V |
| 输入电压： | 2.5 V ~ 20 V |
| PWM 型： | 电压模式 |
| 频率 - 开关： | 900kHz |
| 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： | 26-VFDFN 裸露焊盘 |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | 26-DFN（7x4） |
| 其它名称： | SP7651ER-L/TR-ND |
P ON = I
ON ( RMS )
R ESR ( CIN )
R ESR ≤ I PK - PK
( )
I PP ( – D)
C OUT F S
OutputCapacitorSelection
The required ESR (Equivalent Series Re-
sistance) and capacitance drive the selec-
tion of the type and quantity of the output
capacitors. The ESR must be small enough
that both the resistive voltage deviation due
to a step change in the load current and
the output ripple voltage do not exceed
the tolerance limits expected on the output
voltage. During an output load transient,
the output capacitor must supply all the ad-
ditional current demanded by the load until
the SP7651 adjusts the inductor current to
the new value.
In order to maintain V OUT, the capacitance
must be large enough so that the output
voltage is held up while the inductor current
ramps up or down to the value correspond-
ing to the new load current. Additionally, the
ESR in the output capacitor causes a step
in the output voltage equal to the current.
Because of the fast transient response and
inherent 100% to 0% duty cycle capability
provided by the SP765 when exposed to
an output load transient, the output capacitor
is typically chosen for ESR, not for capaci-
tance value.
The ESR of the output capacitor, combined
with the inductor ripple current, is typically
the main contributor to output voltage ripple.
The maximum allowable ESR required to
maintain a specified output voltage ripple
can be calculated by:
? V OUT
where:
?V OUT = Peak-to-Peak Output Voltage
Ripple
I PK-PK = Peak-to-Peak Inductor Ripple Cur-
rent
The total output ripple is a combination of
the ESR and the output capacitance value
and can be calculated as follows:
2
?V OUT = + (I PP R ESR ) 2
APPLICATIONS INFORMATION
F S = Switching Frequency
D = Duty Cycle
C OUT = Output Capacitance Value
Input Capacitor Selection
The input capacitor should be selected for
ripple current rating, capacitance and volt-
age rating. The input capacitor must meet
the ripple current requirement imposed
by the switching current. In continuous
conduction mode, the source current of
the high-side MOSFET is approximately
a square wave of duty cycle V OUT /V IN .
Most of this current is supplied by the
input bypass capacitors. The RMS value
of input capacitor current is determined at
the maximum output current and under the
assumption that the peak-
to-peak inductor ripple current is low; it is given
by:
I CIN(rms) = I OUT(max) √ D( - D)
The worse case occurs when the duty cycle
D is 50% and gives an RMS current value
equal to I OUT /2. Select input capacitors with
adequate ripple current rating to ensure reli-
able operation.
The power dissipated in the input capaci-
tor is:
2
This can become a significant part of power
losses in a converter and hurt the overall
energy transfer efficiency. The input volt -
age ripple primarily depends on the input
capacitor ESR and capacitance. Ignoring
the inductor ripple current, the input voltage
ripple can be determined by:
?V IN =I OUT ( MAX ) R ESR ( CIN ) +
I OUT ( MAX ) V OUT (V IN -V OUT )
F S C IN V IN2
The capacitor type suitable for the output
capacitors can also be used for the input ca-
pacitors. However, exercise extra caution
Rev J: 3/ 4/07
SP765 Wide Input Voltage Range 3A, 900kHz, Buck Regulator
8
? Copyright 2007 Sipex Corporation
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相关代理商/技术参数 |
参数描述 |
|---|---|
| SP7652 | 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:Wide Input Voltage Range 6A, 600kHz, Buck Regulator |
| SP7652_06 | 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:Wide Input Voltage Range 6A, 600kHz, Buck Regulator |
| SP7652EB | 功能描述:电源管理IC开发工具 Eval Board for SP7652 Series RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V |
| 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 |
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