參數(shù)資料
型號: LTC3867IUF#PBF
廠商: LINEAR TECHNOLOGY CORP
元件分類: 穩(wěn)壓器
英文描述: 0.1 A SWITCHING CONTROLLER, 1200 kHz SWITCHING FREQ-MAX, PQCC24
封裝: 4 X 4 MM, LEAD FREE, PLASTIC, MO-220WGGD, QFN-24
文件頁數(shù): 25/36頁
文件大?。?/td> 380K
代理商: LTC3867IUF#PBF
LTC3867
31
3867f
APPLICATIONS INFORMATION
Figure 16. Branch Current Waveforms
PC Board Layout Checklist
When laying out the printed circuit board, the following
checklist should be used to ensure proper operation of
the IC. These items are also illustrated graphically in the
layout diagram of Figure 16. Check the following in the
PC layout:
1. The INTVCC decoupling capacitor should be placed
immediately adjacent to the IC between the INTVCC pin
and PGND plane. A 1F ceramic capacitor of the X7R
or X5R type is small enough to fit very close to the IC
to minimize the ill effects of the large current pulses
drawn to drive the bottom MOSFETs. An additional
4.7F to 10F of ceramic, tantalum or other very low
ESR capacitance is recommended in order to keep the
internal IC supply quiet.
2. Placethefeedbackdividerbetweenthe+and–terminals
of COUT. Route DIFF+ and DIFFwith minimum PC trace
spacing from the IC to the feedback divider.
3. Are the SENSE+ and SENSEprinted circuit traces
routed together with minimum PC trace spacing? The
filter capacitors between SENSE+ and SENSEshould
be as close as possible to the pins of the IC. Connect
the SENSE+ and SENSEpins to the pads of the sense
resistor as illustrated in Figure 2.
4. Do the (+) plates of CIN connect to the drain of the
topside MOSFET as closely as possible? This capacitor
provides the pulsed current to the MOSFET.
5. Keep the switching nodes, SW, BOOST and TG away
from sensitive small-signal nodes (SENSE+, SENSE,
DIFF+,DIFF,VFB).IdeallytheSW,BOOSTandTGprinted
circuittracesshouldberoutedawayandseparatedfrom
the IC and especially the quiet side of the IC. Separate
the high dv/dt traces from sensitive small-signal nodes
with ground traces or ground planes.
6. Use a low impedance source such as a logic gate to
drive the MODE/PLLIN pin and keep the lead as short
as possible.
7. The 47pF to 330pF ceramic capacitor between the ITH
pin and signal ground should be placed as close as
possible to the IC. Figure 16 illustrates all branch cur-
rents in a switching regulator. It becomes very clear
after studying the current waveforms why it is critical to
keepthehighswitchingcurrentpathstoasmallphysical
size. High electric and magnetic fields will radiate from
these loops just as radio stations transmit signals. The
output capacitor ground should return to the negative
terminal of the input capacitor and not share a com-
mon ground path with any switched current paths. The
left half of the circuit gives rise to the noise generated
by a switching regulator. The ground terminations of
the synchronous MOSFET and Schottky diode should
return to the bottom plate(s) of the input capacitor(s)
with a short isolated PC trace since very high switched
currents are present. External OPTI-LOOP compensa-
tion allows overcompensation for PC layouts which are
not optimized but this is not the recommended design
procedure.
+
RIN
VIN
VOUT
CIN
+
COUT
D1
SW2
SW1
L1
RSENSE
RL
3867 F16
BOLD LINES INDICATE HIGH, SWITCHING CURRENTS. KEEP LINES TO A MINIMUM LENGTH
相關(guān)PDF資料
PDF描述
LTC4000IUFD#PBF 1-CHANNEL POWER SUPPLY MANAGEMENT CKT, PQCC28
LTC4000EUFD#PBF 1-CHANNEL POWER SUPPLY MANAGEMENT CKT, PQCC28
LTC4000EUFD#TRPBF 1-CHANNEL POWER SUPPLY MANAGEMENT CKT, PQCC28
LTC4000IUFD#TRPBF 1-CHANNEL POWER SUPPLY MANAGEMENT CKT, PQCC28
LTC4075XEDD 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO10
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LTC3868EGN-1#PBF 功能描述:IC REG CTRLR BUCK PWM CM 28-SSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:PolyPhase® 標(biāo)準(zhǔn)包裝:2,500 系列:- PWM 型:電流模式 輸出數(shù):1 頻率 - 最大:500kHz 占空比:96% 電源電壓:4 V ~ 36 V 降壓:無 升壓:是 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 125°C 封裝/外殼:24-WQFN 裸露焊盤 包裝:帶卷 (TR)
LTC3868EGN-1#TRPBF 功能描述:IC REG CTRLR BUCK PWM CM 28-SSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:PolyPhase® 標(biāo)準(zhǔn)包裝:2,500 系列:- PWM 型:電流模式 輸出數(shù):1 頻率 - 最大:500kHz 占空比:96% 電源電壓:4 V ~ 36 V 降壓:無 升壓:是 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 125°C 封裝/外殼:24-WQFN 裸露焊盤 包裝:帶卷 (TR)
LTC3868EUFD-1#PBF 功能描述:IC REG CTRLR BUCK PWM CM 28-QFN RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:PolyPhase® 特色產(chǎn)品:LM3753/54 Scalable 2-Phase Synchronous Buck Controllers 標(biāo)準(zhǔn)包裝:1 系列:PowerWise® PWM 型:電壓模式 輸出數(shù):1 頻率 - 最大:1MHz 占空比:81% 電源電壓:4.5 V ~ 18 V 降壓:是 升壓:無 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-5°C ~ 125°C 封裝/外殼:32-WFQFN 裸露焊盤 包裝:Digi-Reel® 產(chǎn)品目錄頁面:1303 (CN2011-ZH PDF) 其它名稱:LM3754SQDKR
LTC3868EUFD-1#TRPBF 功能描述:IC REG CTRLR BUCK PWM CM 28-QFN RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:PolyPhase® 標(biāo)準(zhǔn)包裝:2,500 系列:- PWM 型:電流模式 輸出數(shù):1 頻率 - 最大:500kHz 占空比:96% 電源電壓:4 V ~ 36 V 降壓:無 升壓:是 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 125°C 封裝/外殼:24-WQFN 裸露焊盤 包裝:帶卷 (TR)
LTC3868EUH#PBF 功能描述:IC REG CTRLR BUCK PWM CM 32-QFN RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:PolyPhase® 特色產(chǎn)品:LM3753/54 Scalable 2-Phase Synchronous Buck Controllers 標(biāo)準(zhǔn)包裝:1 系列:PowerWise® PWM 型:電壓模式 輸出數(shù):1 頻率 - 最大:1MHz 占空比:81% 電源電壓:4.5 V ~ 18 V 降壓:是 升壓:無 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-5°C ~ 125°C 封裝/外殼:32-WFQFN 裸露焊盤 包裝:Digi-Reel® 產(chǎn)品目錄頁面:1303 (CN2011-ZH PDF) 其它名稱:LM3754SQDKR