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參數(shù)資料
| 型號： | MP8640DL |
| 廠商： | MONOLITHIC POWER SYSTEMS INC |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | SWITCHING REGULATOR, 800 kHz SWITCHING FREQ-MAX, DSO14 |
| 封裝： | 3 X 4 MM, MO-229VGED-3, QFN-14 |
| 文件頁數(shù)： | 9/10頁 |
| 文件大?。?/td> | 351K |
| 代理商： | MP8640DL |
MP8640 – 3A, 23V, 600KHz STEP-DOWN WITH SYNCHRONOUS GATE DRIVER
MP8640 Rev. 1.0
12/13/2007
www.MonolithicPower.com
9
MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
2007 MPS. All Rights Reserved.
The input capacitor can be electrolytic, tantalum
or ceramic. When using electrolytic or tantalum
capacitors, a small, high quality ceramic
capacitor, i.e. 0.1
μ
F, should be placed as close
to the IC as possible. When using ceramic
capacitors, make sure that they have enough
capacitance to provide sufficient charge to
prevent excessive voltage ripple at input. The
input voltage ripple caused by capacitance can
be estimated by:
V
1
C
f
×
×
×
=
Δ
IN
OUT
V
IN
OUT
V
S
LOAD
I
IN
V
1
V
Selecting the Output Capacitor
The output capacitor (C2) is required to
maintain the DC output voltage. Ceramic,
tantalum, or low ESR electrolytic capacitors are
recommended.
Low
preferred to keep the output voltage ripple low.
The output voltage ripple can be estimated by:
ESR
capacitors
are
×
×
+
×
×
×
=
Δ
2
C
f
8
1
R
V
V
1
L
f
V
V
S
ESR
IN
OUT
S
OUT
OUT
Where L is the inductor value and R
ESR
is the
equivalent series resistance (ESR) value of the
output capacitor.
In the case of ceramic capacitors, the
impedance at the switching frequency is
dominated by the capacitance. The output
voltage ripple is mainly caused by the
capacitance. For simplification, the output
voltage ripple can be estimated by:
×
×
×
×
=
IN
OUT
V
2
S
OUT
V
OUT
V
1
2
C
L
f
8
Δ
V
In the case of tantalum or electrolytic capacitors,
the ESR dominates the impedance at the
switching frequency. For simplification, the
output ripple can be approximated to:
ESR
IN
OUT
V
S
OUT
V
×
OUT
R
V
1
L
f
Δ
V
×
×
=
The characteristics of the output capacitor also
affect the stability of the regulation system. The
MP8640 can be optimized for a wide range of
capacitance and ESR values.
PC Board Layout
The high current paths (GND, IN and SW)
should be placed very to the device with short,
direct and wide traces. The input capacitor
needs to be as close as possible to the IN and
GND pins. The external feedback resistors
should be placed next to the FB pin. Keep the
switching node SW short and away from the
feedback network.
External Bootstrap Diode
An external bootstrap diode may enhance the
efficiency of the regulator, the applicable
conditions of external BST diode are:
z
V
OUT
=5V or 3.3V; and
z
Duty cycle is high: D=
IN
OUT
V
V
>65%
In these cases, an external BST diode is
recommended from the output of the voltage
regulator to BST pin, as shown in Fig.2
External BST Diode
MP8640
SW
BST
C
L
BST
C
5V or 3.3V
OUT
IN4148
Figure 2—Add Optional External Bootstrap
Diode to Enhance Efficiency
The recommended external BST diode is
IN4148, and the BST cap is 0.1~1μF.
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| MP8640DL-LF-P | 功能描述:開關變換器、穩(wěn)壓器與控制器 3A 23V 600kHz Step Dwn w/Sync Gate Drvr RoHS:否 制造商:Texas Instruments 輸出電壓:1.2 V to 10 V 輸出電流:300 mA 輸出功率: 輸入電壓:3 V to 17 V 開關頻率:1 MHz 工作溫度范圍: 安裝風格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel |
| MP8640DL-LF-Z | 功能描述:開關變換器、穩(wěn)壓器與控制器 3A 23V 600kHz Step Dwn w/Sync Gate Drvr RoHS:否 制造商:Texas Instruments 輸出電壓:1.2 V to 10 V 輸出電流:300 mA 輸出功率: 輸入電壓:3 V to 17 V 開關頻率:1 MHz 工作溫度范圍: 安裝風格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel |
| MP8642DU-LF-P | 功能描述:開關變換器、穩(wěn)壓器與控制器 Dual 3A, 23V 600kHz Step-Down RoHS:否 制造商:Texas Instruments 輸出電壓:1.2 V to 10 V 輸出電流:300 mA 輸出功率: 輸入電壓:3 V to 17 V 開關頻率:1 MHz 工作溫度范圍: 安裝風格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel |
| MP8642DU-LF-Z | 功能描述:開關變換器、穩(wěn)壓器與控制器 Dual 3A, 23V 600kHz Step-Down RoHS:否 制造商:Texas Instruments 輸出電壓:1.2 V to 10 V 輸出電流:300 mA 輸出功率: 輸入電壓:3 V to 17 V 開關頻率:1 MHz 工作溫度范圍: 安裝風格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel |
| MP8666DN-LF | 功能描述:開關變換器、穩(wěn)壓器與控制器 6A, 600kHz Step-Down w/Sync Gate Driver RoHS:否 制造商:Texas Instruments 輸出電壓:1.2 V to 10 V 輸出電流:300 mA 輸出功率: 輸入電壓:3 V to 17 V 開關頻率:1 MHz 工作溫度范圍: 安裝風格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel |
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