- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄30767 > LT3511EMS#TRPBF (LINEAR TECHNOLOGY CORP) 0.43 A SWITCHING REGULATOR, 650 kHz SWITCHING FREQ-MAX, PDSO12 PDF資料下載
參數(shù)資料
| 型號： | 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)： | 3/26頁 |
| 文件大小： | 298K |
| 代理商： | LT3511EMS#TRPBF |
第1頁第2頁當(dāng)前第3頁第4頁第5頁第6頁第7頁第8頁第9頁第10頁第11頁第12頁第13頁第14頁第15頁第16頁第17頁第18頁第19頁第20頁第21頁第22頁第23頁第24頁第25頁第26頁
LT3511
11
3511fb
applicaTions inForMaTion
Turns Ratio
Note that when using an RFB/RREF resistor ratio to set
output voltage, the user has relative freedom in selecting
a transformer turns ratio to suit a given application. In
contrast, the use of simple ratios of small integers, e.g.,
1:1, 2:1, 3:2, provides more freedom in setting total turns
and mutual inductance.
Typically, choose the transformer turns to maximize avail-
able output power. For low output voltages (3.3V or 5V), a
N:1 turns ratio can be used with multiple primary windings
relative to the secondary to maximize the transformer’s
current gain (and output power). However, remember that
the SW pin sees a voltage that is equal to the maximum
input supply voltage plus the output voltage multiplied by
the turns ratio. In addition, leakage inductance will cause
a voltage spike (VLEAKAGE) on top of this reflected voltage.
This total quantity needs to remain below the absolute
maximum rating of the SW pin to prevent breakdown of
the internal power switch. Together these conditions place
an upper limit on the turns ratio, N, for a given application.
Choose a turns ratio low enough to ensure:
N <
150V – VIN(MAX) – VLEAKAGE
VOUT + VF
For larger N:1 values, choose a transformer with a larger
physical size to deliver additional current. In addition,
choose a large enough inductance value to ensure that
the off-time is long enough to measure the output voltage.
For lower output power levels, choose a 1:1 or 1:N trans-
former for the absolute smallest transformer size. A 1:N
transformer will minimize the magnetizing inductance
(and minimize size), but will also limit the available output
power. A higher 1:N turns ratio makes it possible to have
veryhighoutputvoltageswithoutexceedingthebreakdown
voltage of the internal power switch.
The turns ratio is an important element in the isolated
feedbackscheme.Makesurethetransformermanufacturer
guarantees turns ratio accuracy within ±1%.
Saturation Current
The current in the transformer windings should not ex-
ceed its rated saturation current. Energy injected once the
core is saturated will not be transferred to the secondary
and will instead be dissipated in the core. Information on
saturation current should be provided by the transformer
manufacturers. Table 1 lists the saturation current of the
transformers designed for use with the LT3511.
Primary Inductance Requirements
The LT3511 obtains output voltage information from the
reflected output voltage on the switch pin. The conduction
of secondary winding current reflects the output voltage
on the primary. The sampling circuitry needs a minimum
of 400ns to settle and sample the reflected output voltage.
Inordertoensurepropersampling,thesecondarywinding
needs to conduct current for a minimum of 400ns. The
following equation gives the minimum value for primary-
side magnetizing inductance:
LPRI ≥
tOFF(MIN) NPS VOUT + VF
(
)
IPEAK(MIN)
tOFF(MIN) = 400ns
IPEAK(MIN) = 55mA
In addition to the primary inductance requirement for
sampling time, the LT3511 has internal circuit constraints
thatpreventtheswitchfromstayingonforlessthan100ns.
If the inductor current exceeds the desired current limit
during that time, oscillation may occur at the output as
the current control loop will lose its ability to regulate.
The following equation, based on maximum input voltage,
must also be followed in selecting primary-side magnetiz-
ing inductance:
LPRI ≥
tON(MIN) VIN(MAX)
IPEAK(MIN)
tON(MIN) = 100ns
IPEAK(MIN) = 55mA
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 |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。