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參數(shù)資料
| 型號： | LT4180IGN#PBF |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 電源管理 |
| 英文描述： | POWER SUPPLY SUPPORT CKT, PDSO24 |
| 封裝： | 0.150 INCH, LEAD FREE, PLASTIC, SSOP-24 |
| 文件頁數(shù)： | 2/18頁 |
| 文件大?。?/td> | 278K |
| 代理商： | LT4180IGN#PBF |
LT4180
10
4180fa
APPLICATIONS INFORMATION
CLOAD =
2.2
RWIRE 2 fDITHER
Where CLOAD istheminimumloaddecouplingcapacitance,
RWIRE is the minimum wiring resistance of one conduc-
tor of the wiring pair, and fDITHER is the minimum dither
frequency.
Continuing the example, our CAT5 cable has a maximum
9.38Ω/100m conductor resistance.
Maximum wiring resistance is:
RWIRE = 2 1000ft 0.305m/ft 0.0938Ω/m
RWIRE = 57.2Ω
With an oscillator tolerance of ±15%, the minimum
dither frequency is 414.8Hz, so the minimum decoupling
capacitance is:
CLOAD =
2.2
57.2
Ω 2 414.8Hz
= 46.36μF
This is the minimum value. Select a nominal value to ac-
count for all factors which could reduce the nominal, such
as initial tolerance, voltage and temperature coefcients
and aging.
CHOLD Capacitor Selection and Compensation
CHOLD1
A 47nF capacitor will sufce for most applications. A
smaller value might allow faster recovery from a sudden
load change, but care must be taken to ensure full load
p-p ripple at this node is kept within 5mV:
CHOLD2
= CHOLD3 =
2.5nF
fDITHER(kHz)
For a dither frequency of 488Hz:
CHOLD2
= CHOLD3 =
2.5nF
0.488(kHz)
= 5.12nF
NPO ceramic or other capacitors with low leakage and di-
electric absorption should be used for all HOLD capacitors.
Set CHOLD4 to 1μF. This value will be adjusted later.
Compensation
Start with a 47pF capacitor between the COMP and DRAIN
pins of the LT4180. Add an RC network in parallel with the
47pF capacitor, 10k and 10nF are good starting values.
Once the output voltage has been conrmed to regulate
at the desired level at no load, increase the load current
to the100% level and monitor the wire current (Dither
Current) with a current probe. Verify the Dither Current
resembles a square-wave with the desired dither frequency.
If the output voltage is too low, increase the value of the
10k resistor until some overshoot is observed at the leading
edge of the dither current waveform. If the output voltage
is still too low, decrease the value of the 10nF capacitor
and repeat the previous step. Repeat this process until the
full load output voltage increases to within 1% below the
no load level. Refer to Figures 7a, 7b and 7c, which show
compensation of the 12V 1.5A Buck Regulator Application
on the datasheet. Check for proper voltage drop correction
over the load range. The “Dither Current” should have
good half-wave symmetry. Namely, waveform should have
similar rise and fall times, enough settling time at top and
bottom and minimum to no over/undershoot.
20μs/DIV
VLOAD
11.2V
IDITHER
50mA/DIV
4180 F07a
Figure 7a. Dither Current and VOUT with
10nF, 10k Compensation 1.5A Load
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參數(shù)描述 |
|---|---|
| LT4180IGN-TRPBF | 制造商:LINER 制造商全稱:Linear Technology 功能描述:Virtual Remote Sense Controller |
| LT4180MPGN#PBF | 功能描述:IC PWR SUPPLY CONTROLLER 24SSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 電源控制器，監(jiān)視器 系列:Virtual Remote Sense™ 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:2,500 系列:- 應(yīng)用:多相控制器 輸入電壓:- 電源電壓:9 V ~ 14 V 電流 - 電源:- 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:40-WFQFN 裸露焊盤 供應(yīng)商設(shè)備封裝:40-TQFN-EP（5x5） 包裝:帶卷 (TR) |
| LT4180MPGN#PBF | 制造商:Linear Technology 功能描述:VIRTUAL REMOTE SENSE CONTROLLER 制造商:Linear Technology 功能描述:IC, REMOTE SENSE CONTROLLER, SSOP-24 |
| LT4180MPGN#TRPBF | 功能描述:IC CTLR REMOTE SENSOR 24SSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 電源控制器，監(jiān)視器 系列:Virtual Remote Sense™ 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:2,500 系列:- 應(yīng)用:多相控制器 輸入電壓:- 電源電壓:9 V ~ 14 V 電流 - 電源:- 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:40-WFQFN 裸露焊盤 供應(yīng)商設(shè)備封裝:40-TQFN-EP（5x5） 包裝:帶卷 (TR) |
| LT4180MPGN-PBF | 制造商:LINER 制造商全稱:Linear Technology 功能描述:Virtual Remote Sense Controller |
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