- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄44995 > LTC3880IUJ#PBF (LINEAR TECHNOLOGY CORP) 0.1 A DUAL SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PQCC40 PDF資料下載
參數(shù)資料
| 型號： | LTC3880IUJ#PBF |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | 0.1 A DUAL SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PQCC40 |
| 封裝： | 6 X 6 MM, LEAD FREE, PLASTIC, WJJD-2, QFN-40 |
| 文件頁數(shù)： | 46/112頁 |
| 文件大?。?/td> | 2182K |
| 代理商： | LTC3880IUJ#PBF |
第1頁第2頁第3頁第4頁第5頁第6頁第7頁第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頁第37頁第38頁第39頁第40頁第41頁第42頁第43頁第44頁第45頁當(dāng)前第46頁第47頁第48頁第49頁第50頁第51頁第52頁第53頁第54頁第55頁第56頁第57頁第58頁第59頁第60頁第61頁第62頁第63頁第64頁第65頁第66頁第67頁第68頁第69頁第70頁第71頁第72頁第73頁第74頁第75頁第76頁第77頁第78頁第79頁第80頁第81頁第82頁第83頁第84頁第85頁第86頁第87頁第88頁第89頁第90頁第91頁第92頁第93頁第94頁第95頁第96頁第97頁第98頁第99頁第100頁第101頁第102頁第103頁第104頁第105頁第106頁第107頁第108頁第109頁第110頁第111頁第112頁
LTC3880/LTC3880-1
39
3880fa
APPLICATIONS INFORMATION
purely inductive component. It was measured using two
scope probes and waveform math to obtain a differential
measurement. Based on additional measurements of the
inductor ripple current and the on-time and off-time of
the top switch, the value of the parasitic inductance was
determined to be 0.5nH using the equation:
ESL
=
VESL(STEP)
IL
tON tOFF
tON + tOFF
(1)
If the RC time constant is chosen to be close to the para-
sitic inductance divided by the sense resistor (L/R), the
resultant waveform looks resistive, as shown in Figure 20.
For applications using low maximum sense voltages,
check the sense resistor manufacturer’s data sheet for
information about parasitic inductance. In the absence
of data, measure the voltage drop directly across the
sense resistor to extract the magnitude of the ESL step
and use Equation 1 to determine the ESL. However, do
not overfilter the signal. Keep the RC time constant less
than or equal to the inductor time constant to maintain a
sufficient ripple voltage on VRSENSE for optimal operation
of the current loop controller.
INDUCTOR DCR CURRENT SENSING
For applications requiring the highest possible efficiency
at high load currents, the LTC3880 is capable of sensing
the voltage drop across the inductor DCR, as shown in
Figure 18a. The DCR of the inductor represents the small
amount of DC winding resistance of the copper, which
can be less than 1mΩ for today’s low value, high current
inductors. In a high current application requiring such an
inductor, conduction loss through a sense resistor would
cost a few points of efficiency compared to DCR sensing.
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 drop across
the inductor DCR multiplied by R2/(R1+R2). R2 scales the
voltage across the sense terminals for applications where
the DCR is greater than the target sense resistor value.
The DCR value is entered as the IOUT_CAL_GAIN in mΩ
unless R2 is required. If R2 is used, IOUT_CAL_GAIN =
DCR R2/(R1+R2). If there is no need to attenuate the
signal, R2 can be removed. To properly dimension the
external filter components, the DCR of the inductor must
be known. It can be measured using a good RLC meter,
but the DCR tolerance is not always the same and varies
with temperature. Consult the manufacturers’ data sheets
for detailed information. The LTC3880 will account for
temperature variation if the correct parameter is entered
into the MFR_IOUT_CAL_GAIN_TC register. Typically the
resistance has a 3900ppm/°C coefficient.
Using the inductor ripple current value from the inductor
Value Calculation section, the target sense resistor value
is:
RSENSE(EQUIV) =
VSENSE(MAX)
IMAX +
IL
2
To ensure that the application will deliver full load current
over the full operating temperature range, be sure to pick
the optimum ILIMIT value accounting for errors in the DCR
versus the MFR_IOUT_CAL_GAIN parameter entered.
Next, determine the DCR of the inductor. Where provided,
use the manufacturer’s maximum value, usually given
at 20°C. Increase this value to account for errors in the
temperature sensing element of 3°C to 5°C and any
Figure 19. Voltage Measured Directly Across RSENSE
Figure 20. Voltage Measured After the RSENSE Filter
500ns/DIV
VSENSE
20mV/DIV
3880 F19
VESL(STEP)
500ns/DIV
VSENSE
20mV/DIV
3880 F20
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LTC3880EUJ-1#TRPBF | 0.1 A DUAL SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PQCC40 |
| LTC3880EUJ-1#PBF | 0.1 A DUAL SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PQCC40 |
| LTC3880IUJ-1#PBF | 0.1 A DUAL SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PQCC40 |
| LTC3890EGN-1#PBF | SWITCHING CONTROLLER, PDSO28 |
| LTC3890IGN-1#TRPBF | SWITCHING CONTROLLER, PDSO28 |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LTC3883EUH#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 24V 1MHZ 0.5/5.5V 32QFN 制造商:Linear Technology 功能描述:BUCK, CNTRL, 24V, 1MHZ, 0.5/5.5V, 32QFN 制造商:Linear Technology 功能描述:PWM CONTROLLER, BUCK, 1MHZ, 24V, QFN-32, Input Voltage:24V, Output Voltage:5.5V, Output Current:30A, Supply Voltage Min:4.5V, Supply Voltage Max:24V, Digital IC Case Style:QFN, No. of Pins:32, Frequency:1MHz, MSL:MSL 1 - Unlimited , RoHS Compliant: Yes 制造商:Linear Technology 功能描述:DP-SWREG/Controller, Digitally Programmable, Multiphase Step-Down DC/DC Controll |
| LTC3883EUH#TRPBF | 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:DP-SWREG/Controller, Digitally Programmable, Multiphase Step-Down DC/DC Controll |
| LTC3883EUH-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 24V 1MHZ 0.5/5.5V 32QFN 制造商:Linear Technology 功能描述:BUCK, CNTRL, 24V, 1MHZ, 0.5/5.5V, 32QFN 制造商:Linear Technology 功能描述:PWM CONTROLLER, BUCK, 1MHZ, 24V, QFN-32, Input Voltage:24V, Output Voltage:5.5V, Output Current:30A, Supply Voltage Min:4.5V, Supply Voltage Max:24V, Digital IC Case Style:QFN, No. of Pins:32, Frequency:1MHz, MSL:MSL 1 - Unlimited , RoHS Compliant: Yes 制造商:Linear Technology 功能描述:DP-SWREG/Controller, Digitally Programmable, Multiphase Step-Down DC/DC Controll |
| LTC3883EUH-1#TRPBF | 制造商:Linear Technology 功能描述:IC REG CTRLR BUCK PWM VM 32-QFN |
| LTC3883IUH#PBF | 制造商:Linear Technology 功能描述:DC DC Cntrlr Single-OUT Sync Step Down 4.5V 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 24V 1MHZ 0.5/5.5V 32QFN 制造商:Linear Technology 功能描述:BUCK, CNTRL, 24V, 1MHZ, 0.5/5.5V, 32QFN 制造商:Linear Technology 功能描述:PWM CONTROLLER, BUCK, 1MHZ, 24V, QFN-32, Input Voltage:24V, Output Voltage:5.5V, Output Current:30A, Supply Voltage Min:4.5V, Supply Voltage Max:24V, Digital IC Case Style:QFN, No. of Pins:32, Frequency:1MHz, MSL:MSL 1 - Unlimited , RoHS Compliant: Yes 制造商:Linear Technology 功能描述:DP-SWREG/Controller, Digitally Programmable, Multiphase Step-Down DC/DC Controll |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。