參數(shù)資料
型號(hào): LT3511EMS#TRPBF
廠商: LINEAR TECHNOLOGY CORP
元件分類: 穩(wěn)壓器
英文描述: 0.43 A SWITCHING REGULATOR, 650 kHz SWITCHING FREQ-MAX, PDSO12
封裝: LEAD FREE, PLASTIC, MSOP-12/16
文件頁數(shù): 8/26頁
文件大小: 298K
代理商: LT3511EMS#TRPBF
LT3511
16
3511fb
DESIGN PROCEDURE/DESIGN EXAMPLE
Use the following design procedure as a guide to design-
ing applications for the LT3511. Remember, the unique
sampling architecture requires an iterative process for
choosing correct resistor values.
The design example involves designing a 15V output with
a 100mA load current and an input range from 36V to 72V.
VIN(MIN) = 36V, VIN(NOM) = 48V, VIN(MAX) = 72V, VOUT =
15V and IOUT = 100mA
Step 1: Select the transformer turns ratio.
NPS <
VSW(MAX) – VIN(MAX) – VLEAKAGE
VOUT + VF
VSW(MAX) = Max rating of internal switch = 150V
VLEAKAGE = Margin for transformer leakage spike = 40V
VF = Forward voltage of output diode = assume approxi-
mately ~ 0.5V
Example:
NPS <
150V – 72V – 40V
15V + 0.5V
NPS < 2.45
NPS = 2
The choice of turns ratio is critical in determining output
power as shown earlier in the Output Power section. At
this point, a third winding can be added to the transformer
to drive the BIAS pin of the LT3511 for higher efficiencies.
Choose a turns ratio that sets the third winding voltage
to regulate between 3.3V and 6V for maximum efficiency.
Choose a third winding ratio to drive BIAS winding with
5V. (Optional)
Example:
NTHIRD
NS
= VTHIRD
VOUT
= 5V
15V
= 0.33
The turns ratio of the transformer chosen is as follows
NPRIMARY: NSECONDARY: NTHIRD = 2:1:0.33.
Step 2: Calculate maximum power output at minimum
VIN.
POUT(VIN(MIN)) = η VIN(MIN) IIN = η VIN(MIN) D
IPEAK 0.5
D =
VOUT + VF
(
) NPS
VOUT + VF
(
) NPS + VIN(MIN)
η = Efficiency = ~75%
IPEAK = Peak switch current = 0.26A
Example:
D = 0.46
POUT(VIN(MIN)) = 1.62
IOUT(VIN(MIN)) = POUT(VIN(MIN))/VOUT = 0.11A
The chosen turns ratio satisfies the output current re-
quirement of 100mA. If the output current was too low,
the minimum input voltage could be adjusted higher. The
turns ratio in this example is set to its highest ratio given
switch voltage requirements and margin for leakage in-
ductance voltage spike.
Step 3: Determine primary inductance, switching fre-
quency and saturation current.
Primary inductance for the transformer must be set above
a minimum value to satisfy the minimum off and on time
requirements.
LPRI
tOFF(MIN) NPS VOUT + VF
(
)
IPEAK(MIN)
tOFF(MIN) = 400ns
IPEAK(MIN) = 55mA
LPRI
tON(MIN) VIN(MAX)
IPEAK(MIN)
tON(MIN) = 100ns
IPEAK(MIN) = 55mA
applicaTions inForMaTion
相關(guān)PDF資料
PDF描述
LT3511MPMS#PBF 0.43 A SWITCHING REGULATOR, 650 kHz SWITCHING FREQ-MAX, PDSO12
LT3511HMS#PBF 0.43 A SWITCHING REGULATOR, 650 kHz SWITCHING FREQ-MAX, PDSO12
LT3512EMS#PBF 0.8 A SWITCHING REGULATOR, 650 kHz SWITCHING FREQ-MAX, PDSO12
LT3512HMS#TRPBF 0.8 A SWITCHING REGULATOR, 650 kHz SWITCHING FREQ-MAX, PDSO12
LT3512MPMS#PBF 0.8 A SWITCHING REGULATOR, 650 kHz SWITCHING FREQ-MAX, PDSO12
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LT3511HMS#PBF 功能描述:IC REG FLYBK ISO ADJ .24A 16MSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關(guān)穩(wěn)壓器 系列:- 設(shè)計(jì)資源:Design Support Tool 標(biāo)準(zhǔn)包裝:1 系列:- 類型:升壓(升壓) 輸出類型:固定 輸出數(shù):1 輸出電壓:3V 輸入電壓:0.75 V ~ 2 V PWM 型:- 頻率 - 開關(guān):- 電流 - 輸出:100mA 同步整流器:是 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:SOT-23-5 細(xì)型,TSOT-23-5 包裝:剪切帶 (CT) 供應(yīng)商設(shè)備封裝:TSOT-23-5 其它名稱:AS1323-BTTT-30CT
LT3511HMS#TRPBF 功能描述:IC REG FLYBK ISO ADJ .24A 16MSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關(guān)穩(wěn)壓器 系列:- 設(shè)計(jì)資源:Design Support Tool 標(biāo)準(zhǔn)包裝:1 系列:- 類型:升壓(升壓) 輸出類型:固定 輸出數(shù):1 輸出電壓:3V 輸入電壓:0.75 V ~ 2 V PWM 型:- 頻率 - 開關(guān):- 電流 - 輸出:100mA 同步整流器:是 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:SOT-23-5 細(xì)型,TSOT-23-5 包裝:剪切帶 (CT) 供應(yīng)商設(shè)備封裝:TSOT-23-5 其它名稱:AS1323-BTTT-30CT
LT3511IMS#PBF 功能描述:IC REG FLYBK ISO ADJ .24A 16MSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關(guān)穩(wěn)壓器 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- 類型:降壓(降壓) 輸出類型:固定 輸出數(shù):1 輸出電壓:1.2V,1.5V,1.8V,2.5V 輸入電壓:2.7 V ~ 20 V PWM 型:- 頻率 - 開關(guān):- 電流 - 輸出:50mA 同步整流器:是 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:10-TFSOP,10-MSOP(0.118",3.00mm 寬)裸露焊盤 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:10-MSOP 裸露焊盤
LT3511IMS#TRPBF 功能描述:IC REG FLYBK ISO ADJ .24A 16MSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關(guān)穩(wěn)壓器 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- 類型:降壓(降壓) 輸出類型:固定 輸出數(shù):1 輸出電壓:1.2V,1.5V,1.8V,2.5V 輸入電壓:2.7 V ~ 20 V PWM 型:- 頻率 - 開關(guān):- 電流 - 輸出:50mA 同步整流器:是 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:10-TFSOP,10-MSOP(0.118",3.00mm 寬)裸露焊盤 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:10-MSOP 裸露焊盤
LT3511MPMS#PBF 功能描述:IC REG FLYBK ISO ADJ .24A 16MSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關(guān)穩(wěn)壓器 系列:- 設(shè)計(jì)資源:Design Support Tool 標(biāo)準(zhǔn)包裝:1 系列:- 類型:升壓(升壓) 輸出類型:固定 輸出數(shù):1 輸出電壓:3V 輸入電壓:0.75 V ~ 2 V PWM 型:- 頻率 - 開關(guān):- 電流 - 輸出:100mA 同步整流器:是 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:SOT-23-5 細(xì)型,TSOT-23-5 包裝:剪切帶 (CT) 供應(yīng)商設(shè)備封裝:TSOT-23-5 其它名稱:AS1323-BTTT-30CT