- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄44994 > LTC3833IFE#PBF (LINEAR TECHNOLOGY CORP) SWITCHING CONTROLLER, 2000 kHz SWITCHING FREQ-MAX, PDSO20 PDF資料下載
參數(shù)資料
| 型號： | LTC3833IFE#PBF |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | SWITCHING CONTROLLER, 2000 kHz SWITCHING FREQ-MAX, PDSO20 |
| 封裝： | 4.40 MM, LEAD FREE, PLASTIC, TSSOP-20 |
| 文件頁數(shù)： | 8/36頁 |
| 文件大?。?/td> | 513K |
| 代理商： | LTC3833IFE#PBF |
第1頁第2頁第3頁第4頁第5頁第6頁第7頁當前第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頁第27頁第28頁第29頁第30頁第31頁第32頁第33頁第34頁第35頁第36頁
LTC3833
16
3833f
APPLICATIONS INFORMATION
Because of possible PCB noise in the current sensing loop,
the current ripple of
VSENSE = IL RSENSE also needs
to be checked in the design to get a good signal-to-noise
ratio. In general, for a reasonably good PCB layout, a
10mV
VSENSEvoltageisrecommendedasaconservative
number to start with, either for RSENSE or DCR sensing
applications.
For today’s highest current density solutions the value of
the sense resistor can be less than 1mΩ and the maxi-
mum sense voltage can be as low as 30mV. In addition,
inductor ripple currents greater than 50% with operation
up to 2MHz are becoming more common. Under these
conditions, the voltage drop across the sense resistor’s
parasitic inductance becomes more relevant. A small RC
filter placed near the IC has been traditionally used to re-
duce the effects of capacitive and inductive noise coupled
in the sense traces on the PCB. A typical filter consists of
two series 10Ω resistors connected to a parallel 1000pF
capacitor, resulting in a time constant of 20ns.
The filter components need to be placed close to the IC.
The positive and negative sense traces need to be routed
as a differential pair and Kelvin (4-wire) connected to the
sense resistor.
DCR Inductor Current Sensing
For applications requiring higher efficiency at high load
currents, the LTC3833 is capable of sensing the voltage
drop across the inductor DCR, as shown in Figure 4.
The DCR of the inductor represents the small amount of
DC winding resistance, which can be less than 1mΩ for
today’s low value, high current inductors. In a high cur-
rent application requiring such an inductor, conduction
loss through a sense resistor would cost several points
of efficiency compared to DCR sensing.
The inductor DCR is sensed by connecting an RC filter
across the inductor. This filter typically consists of one
or two resistors (R1 and R2) and one capacitor (C1) as
shown in Figure 4. If the external R1||R2 C1 time constant
is chosen to be exactly equal to the L/DCR time constant,
the voltage drop across the external capacitor is equal
to the voltage drop across the inductor DCR multiplied
by R2/(R1 + R2). Therefore, R2 may be used to scale
the voltage across the sense terminals when the DCR is
greater than the target sense resistance. With the ability
to program current limit through the VRNG pin, R2 may
be optional. C1 is usually selected to be in the range of
0.01μF to 0.47μF. This forces R1|| R2 to around 2k to 4k,
reducing error that might have been caused by the SENSE
pins’ input bias currents.
The first step in designing DCR current sensing is to
determine the DCR of the inductor. Where provided, use
the manufacturer’s maximum value, usually given at 25°C.
Increase this value to account for the temperature coef-
ficient of resistance, which is approximately 0.4%/°C. A
conservative value for inductor temperature TL is 100°C.
TheDCRoftheinductorcanalsobemeasuredusingagood
RLC meter, but the DCR tolerance is not always the same
and varies with temperature; consult the manufacturers’
datasheets for detailed information.
From the DCR value, VSENSE(MAX) is calculated as:
VSENSE(MAX) =DCRMAX at 25°C 1+0.4% TL(MAX) –25°C
(
)
IOUT(MAX) – IL/2
If VSENSE(MAX) is within the maximum sense voltage of
the LTC3833 as programmed by the VRNG pin (30mV to
100mV), then the RC filter only needs R1. If VSENSE(MAX)is
higher, then R2 may be used to scale down the maximum
sense voltage so that it falls within range.
The maximum power loss in R1 is related to duty cycle,
and will occur in continuous mode at the maximum input
voltage:
PLOSS R1
( )=
VIN(MAX) – VOUT
(
)V
OUT
R1
R2
(OPT)
DCR
L
INDUCTOR
L/DCR = (R1||R2) C1
C1 NEAR SENSE PINS
SENSE+
LTC3833
SENSE–
C1
3833 F04
VOUT
COUT
Figure 4. DCR Current Sensing
相關PDF資料 |
PDF描述 |
|---|---|
| LTC3835IGN-1#TR | 3 A SWITCHING CONTROLLER, 580 kHz SWITCHING FREQ-MAX, PDSO16 |
| LTC3835EDHC-1#TRPBF | 3 A SWITCHING CONTROLLER, 580 kHz SWITCHING FREQ-MAX, PDSO16 |
| LTC3835IGN-1 | 3 A SWITCHING CONTROLLER, 580 kHz SWITCHING FREQ-MAX, PDSO16 |
| LTC3835IUFD | 3 A SWITCHING CONTROLLER, 580 kHz SWITCHING FREQ-MAX, PQCC20 |
| LTC3850EUF | 0.1 A DUAL SWITCHING CONTROLLER, 860 kHz SWITCHING FREQ-MAX, PQCC28 |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| LTC3833IUDC#PBF | 功能描述:IC REG CTRLR BUCK PWM CM 20-QFN RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標準包裝: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) |
| LTC3833IUDC#TRPBF | 功能描述:IC REG CTRLR BUCK PWM CM 20-QFN RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標準包裝: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) |
| LTC3834EDHC-1#PBF | 功能描述:IC REG CTRLR BUCK PWM CM 16-DFN RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標準包裝:2,000 系列:- PWM 型:電流模式 輸出數(shù):1 頻率 - 最大:1MHz 占空比:50% 電源電壓:9 V ~ 10 V 降壓:無 升壓:是 回掃:是 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 85°C 封裝/外殼:8-TSSOP（0.173"，4.40mm 寬） 包裝:帶卷 (TR) |
| LTC3834EDHC-1#TRPBF | 功能描述:IC REG CTRLR BUCK PWM CM 16-DFN RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標準包裝: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) |
| LTC3834EFE#PBF | 功能描述:IC REG CTRLR BUCK PWM CM 20TSSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 特色產(chǎn)品:LM3753/54 Scalable 2-Phase Synchronous Buck Controllers 標準包裝: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 |
發(fā)布緊急采購，3分鐘左右您將得到回復。