參數(shù)資料
型號(hào): LTC3860IUH#PBF
廠商: LINEAR TECHNOLOGY CORP
元件分類: 穩(wěn)壓器
英文描述: DUAL SWITCHING CONTROLLER, 1250 kHz SWITCHING FREQ-MAX, PQCC32
封裝: 5 X 5 MM, LEAD FREE, PLASTIC, MO-220WHHD, QFN-32
文件頁(yè)數(shù): 17/36頁(yè)
文件大?。?/td> 436K
代理商: LTC3860IUH#PBF
LTC3860
24
3860fc
APPLICATIONS INFORMATION
Once the value of resistor R1, poles and zeros location
have been decided, the value of R2, C1, C2, R3 and C3
can be obtained from the previous equations.
Compensating a switching power supply feedback loop
is a complex task. The applications shown in this data
sheet show typical values, optimized for the power
components shown. Though similar power compon-
ents should sufce, substantially changing even one
major power component may degrade performance
signicantly. Stability also may depend on circuit board
layout. To verify the calculated component values, all
new circuit designs should be prototyped and tested
for stability.
Inductor
The inductor in a typical LTC3860 circuit is chosen for a
specic ripple current and saturation current. Given an
input voltage range and an output voltage, the inductor
value and operating frequency directly determine the
ripple current. The inductor ripple current in the buck
mode is:
ΔI
L =
V
OUT
(f)(L)
1–
V
OUT
V
IN
Lower ripple current reduces core losses in the inductor,
ESR losses in the output capacitors and output voltage
ripple. Thus highest efciency operation is obtained at
low frequency with small ripple current. To achieve this
however, requires a large inductor.
A reasonable starting point is to choose a ripple cur-
rent between 20% and 40% of IO(MAX). Note that the
largest ripple current occurs at the highest VIN. To guar-
antee that ripple current does not exceed a specied
maximum, the inductor in buck mode should be chosen
according to:
L
V
OUT
f
ΔI
L(MAX)
1–
V
OUT
V
IN(MAX)
Power MOSFET Selection
The LTC3680 requires at least two external N-channel power
MOSFETs per channel, one for the top (main) switch and
one or more for the bottom (synchronous) switch. The
number, type and on-resistance of all MOSFETs selected
take into account the voltage step-down ratio as well as
the actual position (main or synchronous) in which the
MOSFET will be used. A much smaller and much lower
input capacitance MOSFET should be used for the top
MOSFET in applications that have an output voltage that
is less than 1/3 of the input voltage. In applications where
VIN >> VOUT, the top MOSFETs’ on-resistance is normally
less important for overall efciency than its input capaci-
tance at operating frequencies above 300kHz. MOSFET
manufacturers have designed special purpose devices that
provide reasonably low on-resistance with signicantly
reduced input capacitance for the main switch application
in switching regulators.
Selection criteria for the power MOSFETs include the on-
resistance RDS(ON), input capacitance, breakdown voltage
and maximum output current.
For maximum efciency, on-resistance RDS(ON) and input
capacitance should be minimized. Low RDS(ON) minimizes
conduction losses and low input capacitance minimizes
switching and transition losses. MOSFET input capacitance
is a combination of several components but can be taken
from the typical “gate charge” curve included on most
data sheets (Figure 13).
+
VDS
VIN
VGS
MILLER EFFECT
QIN
ab
CMILLER = (QB – QA)/VDS
VGS
V
+
3860 F12
Figure 13. Gate Charge Characteristic
相關(guān)PDF資料
PDF描述
LTC3862HUH#TRPBF DUAL SWITCHING CONTROLLER, 500 kHz SWITCHING FREQ-MAX, QCC24
LTC3862IFE#PBF DUAL SWITCHING CONTROLLER, 500 kHz SWITCHING FREQ-MAX, PDSO24
LTC3862HFE#PBF DUAL SWITCHING CONTROLLER, 500 kHz SWITCHING FREQ-MAX, PDSO24
LTC3862EGN#TRPBF DUAL SWITCHING CONTROLLER, 500 kHz SWITCHING FREQ-MAX, PDSO24
LTC3862IUH#PBF DUAL SWITCHING CONTROLLER, 500 kHz SWITCHING FREQ-MAX, QCC24
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LTC3861EUH-1#PBF 制造商:Linear Technology 功能描述:IC REG CTRLR BUCK PWM VM 32-QFN 制造商:Linear Technology 功能描述:BUCK CNTRL DUAL 12PH 2.25MHZ 32QFN 制造商:Linear Technology 功能描述:BUCK, CNTRL, DUAL, 12PH, 2.25MHZ, 32QFN 制造商:Linear Technology 功能描述:PWM CONTROLLER, BUCK, 2.25MHZ, 24V, QFN-32, Input Voltage:24V, Output Voltage:5.5V, Output Current:60A, Supply Voltage Min:3V, Supply Voltage Max:5.5V, Digital IC Case Style:QFN, No. of Pins:32, Frequency:2.25MHz , RoHS Compliant: Yes 制造商:Linear Technology 功能描述:DP-SWREG/Controller, Dual-Phase/Dual-Channel Step-Down Voltage Mode Controller w
LTC3861EUH-1#TRPBF 制造商:Linear Technology 功能描述:IC REG CTRLR BUCK PWM VM 32-QFN
LTC3861EUHE#PBF 功能描述:IC REG CTRLR BUCK PWM VM 36-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:4,500 系列:PowerWise® PWM 型:控制器 輸出數(shù):1 頻率 - 最大:1MHz 占空比:95% 電源電壓:2.8 V ~ 5.5 V 降壓:是 升壓:無(wú) 回掃:無(wú) 反相:無(wú) 倍增器:無(wú) 除法器:無(wú) Cuk:無(wú) 隔離:無(wú) 工作溫度:-40°C ~ 125°C 封裝/外殼:6-WDFN 裸露焊盤(pán) 包裝:帶卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名稱:LM1771SSDX
LTC3861EUHE#TRPBF 功能描述:IC REG CTRLR BUCK PWM VM 36-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(wú) 升壓:是 回掃:無(wú) 反相:無(wú) 倍增器:無(wú) 除法器:無(wú) Cuk:無(wú) 隔離:無(wú) 工作溫度:-40°C ~ 125°C 封裝/外殼:24-WQFN 裸露焊盤(pán) 包裝:帶卷 (TR)
LTC3861IUH-1#PBF 制造商:Linear Technology 功能描述:DC DC Cntrlr Dual-OUT Sync Step Down 3V to 24V Input 32-Pin QFN EP 制造商:Linear Technology 功能描述:IC REG CTRLR BUCK PWM VM 32-QFN 制造商:Linear Technology 功能描述:BUCK CNTRL DUAL 12PH 2.25MHZ 32QFN 制造商:Linear Technology 功能描述:BUCK, CNTRL, DUAL, 12PH, 2.25MHZ, 32QFN 制造商:Linear Technology 功能描述:DP-SWREG/Controller, Dual-Phase/Dual-Channel Step-Down Voltage Mode Controller w 制造商:Linear Technology 功能描述:PWM CONTROLLER, BUCK, 2.25MHZ, 24V, QFN-32, Input Voltage:24V, Output Voltage:5.5V, Output Current:60A, Supply Voltage Min:3V, Supply Voltage Max:5.5V, Digital IC Case Style:QFN, No. of Pins:32, Frequency:2.25MHz , RoHS Compliant: Yes