欧美成人免费电影,国产欧美一区二区三区精品酒店,精品国产a毛片,色网在线免费观看

參數資料
型號: FAN5231
廠商: FAIRCHILD SEMICONDUCTOR CORP
元件分類: 穩壓器
英文描述: Micropower 5V, 100mA Low Dropout Linear Regulator
中文描述: 1 A SWITCHING REGULATOR, 345 kHz SWITCHING FREQ-MAX, PDSO28
封裝: QSOP-28
文件頁數: 14/17頁
文件大小: 360K
代理商: FAN5231
FAN5231
14
REV. 1.1.1 8/15/01
MOSFET Selection and Considerations
Requirements for upper and lower MOSFETs are different
in mobile applications. The reason for this is the 10:1 differ-
ence in conduction time of the lower and the upper MOS-
FETs driven by a difference between the input voltage which
is nominally in the range from 8V to 20V and output voltage
which is about 1.5V.
Requirements for the lower MOSFET are simpler than those
for the upper one. The lower the Rdson of this device the
lower the conduction losses, and the higher converter’s
efficiency. Switching losses and gate drive losses are not
significant because of zero-voltage switching conditions
inherent for this device in the buck converter. Important is
low reverse recovery charge of the body diode which causes
shoot-trough current spikes when the upper MOSFET turns
on. Also, important is to verify that the lower MOSFET gate
voltage does not reach threshold when high dV/dt transition
occurs on the phase node. Specially for that reason,
FAN5231 is equipped with a low, 1.0
typical, pull-down
resistance of low side driver.
Requirements for the upper MOSFET Rdson are less
stringent than for the lower MOSFET because its conduction
time is significantly shorter while switching losses can
dominate especially at higher input voltages. It is recom-
mended to have equal conduction and switching losses in the
upper MOSFET at the nominal input voltage and load
current. In this case maximum converter efficiency is tuned
to the operation point that it is most desired.
Precise calculation of power dissipation in the MOSFETs is
very complex because many parameters affecting turn-on
and turn-off times such as gate reverse transfer charge, gate
internal resistance, body diode reverse recovery charge,
package and layout impedances and their variation with the
operation conditions are not available to a designer. Follow-
ing equations are provided only for crude estimation of the
power losses and should be accompanied by a detail bread-
board evaluation. Attention should be paid to the input
voltage extremes where power dissipation in the MOSFETs
is usually higher.
Plower
Io
2
Rdson
1
V
in
----out
×
×
=
Pupper
2
-o
Rdson
V
in
Vout
×
×
-o
Vin
Fs
ton
toff
+
(
)
×
×
×
2
+
=
相關PDF資料
PDF描述
FAN5231QSC Analog IC
FAN5232 Adjustable PWM Buck Controller for LCD PCs
FAN5232MTC SMPS Controller
FAN5233 System Electronics Regulator for Mobile PCs
FAN5233MTC Analog IC
相關代理商/技術參數
參數描述
FAN5231 WAF 制造商:Fairchild Semiconductor Corporation 功能描述:
FAN5231QSC 功能描述:開關變換器、穩壓器與控制器 QSOP-28 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
FAN5231QSCX 功能描述:開關變換器、穩壓器與控制器 QSOP-28 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
FAN5232 制造商:FAIRCHILD 制造商全稱:Fairchild Semiconductor 功能描述:Adjustable PWM Buck Controller for LCD PCs
FAN5232_CBC3116B WAF 制造商:Fairchild Semiconductor Corporation 功能描述:
主站蜘蛛池模板: 泸水县| 香河县| 乐业县| 克拉玛依市| 河曲县| 溧阳市| 舟山市| 石嘴山市| 德昌县| 句容市| 清水河县| 云和县| 呈贡县| 新干县| 瓮安县| 宝清县| 六枝特区| 静乐县| 浏阳市| 科技| 茶陵县| 丰都县| 屏东市| 徐水县| 宜阳县| 广南县| 江安县| 阿克苏市| 讷河市| 苏尼特右旗| 扶余县| 杭锦旗| 女性| 买车| 吐鲁番市| 宣恩县| 新安县| 杭锦旗| 四会市| 偃师市| 西宁市|