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参数资料
| 型号： | LT3495EDDB#TRMPBF |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 稳压器 |
| 英文描述： | 0.78 A SWITCHING REGULATOR, PDSO10 |
| 封装： | 3 X 2 MM, LEAD FREE, PLASTIC, MO-229WECD-1, DFN-10 |
| 文件页数： | 3/16页 |
| 文件大小： | 299K |
| 代理商： | LT3495EDDB#TRMPBF |
LT3495/LT3495B/
LT3495-1/LT3495B-1
11
3495b1b1fa
APPLICATIONS INFORMATION
Maximum Output Load Current
The maximum output current of a particular LT3495 series
circuit is a function of several circuit variables. The fol-
lowing method can be helpful in predicting the maximum
load current for a given circuit:
Step 1: Calculate the peak inductor current:
I
PK = ILIMIT +
V
IN 200 10
–9
L
amps
where ILIMIT is 0.65A and 0.35A for LT3495/LT3495B and
LT3495-1/LT3495B-1 respectively. L is the inductance
value in Henrys and VIN is the input voltage to the boost
circuit.
Step 2: Calculate the inductor ripple current:
I
RIPPLE =
V
OUT + 1– VIN
()20010–9
L
amps
where VOUT is the desired output voltage. If the inductor
ripple current is greater than the peak current, then the
circuit will only operate in discontinuous conduction mode.
The inductor value should be increased so that IRIPPLE<IPK.
An application circuit can be designed to operate only in
discontinuous mode, but the output current capability
will be reduced.
Step 3: Calculate the average input current:
I
IN(AVG) = IPK –
I
RIPPLE
2
amps
Step 4: Calculate the nominal output current:
I
OUT(NOM) =
I
IN(AVG) VIN 0.8
V
OUT
amps
Step 5: Derate output current:
IOUT = IOUT(NOM) 0.8 amps
For low output voltages the output current capability will
be increased. When using output disconnect (load cur-
rent taken from VOUT), these higher currents will cause
the drop in the PMOS switch to be higher resulting in
reduced output current capability than those predicted
by the preceding equations.
Inrush Current
When VCC is stepped from ground to the operating voltage
while the output capacitor is discharged, a higher level of
inrush current may ow through the inductor and Schottky
diode into the output capacitor. Conditions that increase
inrush current include a larger more abrupt voltage step
at VIN, a larger output capacitor tied to the CAP pin and an
inductor with a low saturation current. While the chip is
designed to handle such events, the inrush current should
not be allowed to exceed 1.5A. For circuits that use output
capacitor values within the recommended range and have
input voltages of less than 5V, inrush current remains low,
posing no hazard to the device. In cases where there are
large steps at VCC (more than 5V) and/or a large capacitor
is used at the CAP pin, inrush current should be measured
to ensure safe operation.
Soft-Start
By connecting the SHDN and CTRL pins as shown in
Figure 4, using an RC lter at the CTRL pin to limit the
start-up current, the LT3495 is able to achieve soft-start.
The small bias current of the CTRL pin allows using a
small capacitor for a large RC time constant. The soft-
start waveform is shown in Figure 5. The soft-start time
Figure 5. Soft-Start Waveform
Figure 4. Soft-Start Circuitry
SW
CAP
VCC
SHDN
CTRL
VOUT
FB
GND
3495 F04
LT3495
CCTRL
RCTRL
CHIP ENABLE
500μs/DIV
3495 F05
SHDN VOLTAGE
5V/DIV
INDUCTOR CURRENT
500mA/DIV
VOUT VOLTAGE
5V/DIV
CTRL VOLTAGE
2V/DIV
VCC = 3.6V
VOUT = 16V
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LT3495EDDB-TRPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:650mA/350mA Micropower Low Noise Boost Converter with Output Disconnect |
| LT3496 | 制造商:LINER 制造商全称:Linear Technology 功能描述:16-Channel 50mA LED |
| LT3496EFE#PBF | 功能描述:IC LED DRVR WT/RGB BCKLT 28TSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - LED 驱动器 系列:- 标准包装:60 系列:- 恒定电流:- 恒定电压:- 拓扑:线性（LDO），PWM，升压（升压） 输出数:8 内部驱动器:是 类型 - 主要:背光 类型 - 次要:RGB，白色 LED 频率:500kHz ~ 1.5MHz 电源电压:4.75 V ~ 26 V 输出电压:45V 安装类型:* 封装/外壳:* 供应商设备封装:* 包装:* 工作温度:-40°C ~ 85°C |
| LT3496EFE#TRPBF | 功能描述:IC LED DRVR WT/RGB BCKLT 28TSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - LED 驱动器 系列:- 标准包装:6,000 系列:- 恒定电流:- 恒定电压:- 拓扑:开路漏极，PWM 输出数:4 内部驱动器:是 类型 - 主要:LED 闪烁器 类型 - 次要:- 频率:400kHz 电源电压:2.3 V ~ 5.5 V 输出电压:- 安装类型:表面贴装 封装/外壳:8-VFDFN 裸露焊盘 供应商设备封装:8-HVSON 包装:带卷 (TR) 工作温度:-40°C ~ 85°C 其它名称:935286881118PCA9553TK/02-TPCA9553TK/02-T-ND |
| LT3496EFE-PBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:Triple Output LED Driver |
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