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參數(shù)資料
| 型號： | LT3509EDE#PBF |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | 1.2 A DUAL SWITCHING CONTROLLER, 2500 kHz SWITCHING FREQ-MAX, PDSO14 |
| 封裝： | 4 X 3 MM, LEAD FREE, PLASTIC, MO-229WGED-3, DFN-14 |
| 文件頁數(shù)： | 24/24頁 |
| 文件大?。?/td> | 271K |
| 代理商： | LT3509EDE#PBF |
LT3509
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3509fc
APPLICATIONS INFORMATION
Shutdown and Soft Start
When the RUN/SS pins are pulled to ground, the part will
shut down to its lowest current state of approximately
9μA. If driving a large capacitive load it may be desirable
to use the current limiting soft-start feature. Connecting
capacitors to ground from the RUN/SS pins will control
the delay until full current is available. The pull-up current
is 1μA and the full current threshold is 2V so the start-up
time is given by:
T = 2 C 106 s
For example a 0.005μF capacitor will give a time to full
current of 10ms. If both outputs can come up together
then the two inputs can be paralleled and tied to one ca-
pacitor. In this case use twice the capacitor value to obtain
the same start-up time. During the soft-start time both
the peak current threshold and the DA current threshold
will track so the part will skip pulses as required to limit
the maximum inductor current. Starting up into a large
capacitor is not much different to starting into a short-
circuit in this respect.
Setting The Output Voltage
The output voltage is programmed with a resistor divider
between the output and the FB pin. Choose the resistors
according to:
R1=R2
VOUT
0.8
–1
The designators correspond to Figure 1. R2 should be 20k
or less to avoid bias current errors.
Frequency Setting
The timing resistor, RT, for any desired frequency in the
range 264kHz to 2.2MHz can be calculated from the
following formula:
RT =
1.215
fSW
– 0.215 40.2
where fSW is in MHz and RT is in kΩ.
Table 1. Standard E96 Resistors for Common Frequencies
FREQUENCY
TIMING RESISTOR RT (kΩ)
264 kHz
178
300 kHz
154
400kHz
113
500kHz
88.7
1MHz
40.2
2MHz
15.8
2.2MHz
13.7
Note: The device is specied for operation down to 300kHz. The 264kHz
value is to allow external synchronization at 300kHz
Figure 2. Soft-Start
IL
0.2A/DIV
VSW
10V/DIV
VOUT
5V/DIV
TIME 1ms/DIV
3509 F02
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相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| LT3509EDE-TRPBF | 制造商:LINER 制造商全稱:Linear Technology 功能描述:Dual 36V, 700mA Step-Down Regulator |
| LT3509EMSE#PBF | 功能描述:IC REG BUCK ADJ 0.7A DL 16MSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關穩(wěn)壓器 系列:- 標準包裝:250 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 輸入電壓:2.05 V ~ 6 V PWM 型:電壓模式 頻率 - 開關:2MHz 電流 - 輸出:500mA 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:6-UFDFN 包裝:帶卷 (TR) 供應商設備封裝:6-SON（1.45x1） 產(chǎn)品目錄頁面:1032 (CN2011-ZH PDF) 其它名稱:296-25628-2 |
| LT3509EMSE#TRPBF | 功能描述:IC REG BUCK ADJ 0.7A DL 16MSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關穩(wěn)壓器 系列:- 標準包裝: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:- 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) 供應商設備封裝:10-MSOP 裸露焊盤 |
| LT3509EMSEPBF | 制造商:Linear Technology 功能描述:Conv DC-DC Dual Step-Down 3.6-36V MSOP16 |
| LT3509EMSE-PBF | 制造商:LINER 制造商全稱:Linear Technology 功能描述:Dual 36V, 700mA Step-Down Regulator |
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