參數(shù)資料
型號(hào)： LM5027AMH
廠商： NATIONAL SEMICONDUCTOR CORP
元件分類(lèi)： 穩(wěn)壓器
英文描述： SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PDSO20
封裝： TSSOP-20
文件頁(yè)數(shù)： 13/28頁(yè)
文件大?。?/td> 561K
代理商： LM5027AMH
For Applications > 100V
For applications where the system input voltage (V
PWR) ex-
ceeds 100V, VIN can be powered from an external start-up
regulator as shown in Figure 11. Connecting the VIN and VCC
pins together allows the LM5027A to be operated with VIN
below 13V. To turn-off the internal start-up regulator the VCC
voltage must be raised above 9.9V. The voltage at the VCC
pin must not exceed 15V. The voltage source at the right side
of Figure 11 is typically derived from the power stage, and
becomes active when the LM5027A outputs are active.
30111914
FIGURE 11. Start-up Regulator for V
PWR > 100V
UVLO
The under-voltage lockout threshold (UVLO) is internally set
to 2.0V at the UVLO pin. With two external resistors as shown
in Figure 12, the LM5027A is enabled when V
PWR causes the
UVLO pin to exceed threshold voltage of 2V. When V
PWR is
below the threshold, the internal 20 A current sink is enabled
to reduce the voltage at the UVLO pin. When the UVLO pin
voltage exceeds the 2V threshold, the 20 A current sink is
turned off causing the UVLO voltage to increase and provid-
ing hysteresis. The values of R1 and R2 can be determined
from the following equation:
R1 = V
HYS/20 A
Where V
HYS is the desired UVLO hysteresis at VPWR, and
V
PWR in the second equation is the turn-on voltage. For ex-
ample, if the LM5027A is to be enabled when V
PWR reaches
34V, and the hysteresis is 1.8V, then R1 is 90 k
and 5.6
k
. For this application R1 was selected to be 90.0 k, R2
was selected to be 6.19 k
. The LM5027A can be remotely
shutdown by taking the UVLO pin below 0.4V with an external
open collector or open drain device, as shown in Figure 12.
The outputs and the VCC regulator are disabled in shutdown
mode.
www.national.com
20
LM5027A
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LM5027AMH/NOPB 功能描述:電壓模式 PWM 控制器 Active Clamp Pwm W/3A Sr Drv RoHS:否 制造商:Texas Instruments 輸出端數(shù)量:1 拓?fù)浣Y(jié)構(gòu):Buck 輸出電壓:34 V 輸出電流: 開(kāi)關(guān)頻率: 工作電源電壓:4.5 V to 5.5 V 電源電流:600 uA 最大工作溫度:+ 125 C 最小工作溫度:- 40 C 封裝 / 箱體:WSON-8 封裝:Reel
LM5027AMHX/NOPB 功能描述:電壓模式 PWM 控制器 RoHS:否 制造商:Texas Instruments 輸出端數(shù)量:1 拓?fù)浣Y(jié)構(gòu):Buck 輸出電壓:34 V 輸出電流: 開(kāi)關(guān)頻率: 工作電源電壓:4.5 V to 5.5 V 電源電流:600 uA 最大工作溫度:+ 125 C 最小工作溫度:- 40 C 封裝 / 箱體:WSON-8 封裝:Reel
LM5027ASQ/NOPB 功能描述:電壓模式 PWM 控制器 RoHS:否 制造商:Texas Instruments 輸出端數(shù)量:1 拓?fù)浣Y(jié)構(gòu):Buck 輸出電壓:34 V 輸出電流: 開(kāi)關(guān)頻率: 工作電源電壓:4.5 V to 5.5 V 電源電流:600 uA 最大工作溫度:+ 125 C 最小工作溫度:- 40 C 封裝 / 箱體:WSON-8 封裝:Reel
LM5027ASQX/NOPB 功能描述:電壓模式 PWM 控制器 RoHS:否 制造商:Texas Instruments 輸出端數(shù)量:1 拓?fù)浣Y(jié)構(gòu):Buck 輸出電壓:34 V 輸出電流: 開(kāi)關(guān)頻率: 工作電源電壓:4.5 V to 5.5 V 電源電流:600 uA 最大工作溫度:+ 125 C 最小工作溫度:- 40 C 封裝 / 箱體:WSON-8 封裝:Reel
LM5027MH 制造商:NSC 制造商全稱(chēng):National Semiconductor 功能描述:Voltage Mode Active Clamp Controller
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