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參數(shù)資料
| 型號： | FAN5063M |
| 廠商： | FAIRCHILD SEMICONDUCTOR CORP |
| 元件分類： | 模擬信號調(diào)理 |
| 英文描述： | Power Supply Switching Circuit |
| 中文描述： | SPECIALTY ANALOG CIRCUIT, PDSO16 |
| 封裝： | SOIC-16 |
| 文件頁數(shù)： | 12/14頁 |
| 文件大小： | 196K |
| 代理商： | FAN5063M |
FAN5063
PRODUCT SPECIFICATION
12
REV. 1.0.0 12/4/00
Alternate for Adjustable Dual
I
nstead of the bipolar transistor shown in Figure 4 for Q3, the
linear pass element for the adjustable dual, a MOSFET and
schottky diode can be used as shown in Figure 7.
Figure 7. Adjustable Dual with MOSFET
The schottky should be chosen to have a low V
f
at the speci-
fied adjustable voltage and current. The MOSFET’s R
DS,on
must then be lower than (5V -5% -VADJ -V
f
)/I
Dual
including
temperature. An additional constraint is that the MOSFET
must have a gate threshold voltage lower than 1.5V. For exam-
ple, for 2.8A @3.3V, choose the diode to be an MBR835, and
the MOSFET a Fairchild FDC653M. This same technique
can then also be used for adjustable currents higher than can
be achieved with the bipolar transistor.
Output Capacitor Selection
Output capacitor selection depends on whether the line has
overlap time or not.
For both the adjustable dual, there is guaranteed overlap time
between when one source is turned on and the other source
turned off. For this output, the output capacitor is not needed
to hold up the supply, but only for noise filtering and to
respond to transient loading.
The 3.3V dual output has deadtime between when one
source is turned off and the other source turned on. During
the time when both are off, the output current must be sup-
plied by the output capacitor. Mitigating this, it must be real-
ized that the system will be designed in such a way that the
current has gone to its sleep value before the transition
occurs. For example, the 3.3V dual has a sleep current of
500mA maximum. Maximum deadtime is 6μsec, and so
charge depletion is 500mA * 6μsec = 3μC. Suppose that we
have a total of 8% drop due to the source tolerance and the
MOSFET drop, and we are trying to hold 10% regulation.
The remaining 2% = 66mV implies a minimum capacitance
of 3μC/66mV = 45μF.
FAN5063
14
5V Main
Adjustable Dual
12
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| FAN5063MX | 功能描述:開關(guān)變換器、穩(wěn)壓器與控制器 aCPI Dual Switch Controller 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(guān)頻率:1 MHz 工作溫度范圍: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel |
| FAN5063-ZCA3026B WAF | 制造商:Fairchild Semiconductor Corporation 功能描述: |
| FAN5066 | 制造商:FAIRCHILD 制造商全稱:Fairchild Semiconductor 功能描述:Ultra Low Voltage Synchronous DC-DC Controller |
| FAN5066A WAF | 制造商:Fairchild Semiconductor Corporation 功能描述: |
| FAN5066A-3116B WAF | 制造商:Fairchild Semiconductor Corporation 功能描述: |
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