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参数资料
| 型号： | LT3581EMSE#PBF |
| 厂商： | Linear Technology |
| 文件页数： | 18/36页 |
| 文件大小： | 0K |
| 描述： | IC REG MULTI CONFIG ADJ 16MSOP |
| 标准包装： | 37 |
| 类型： | 升压（升压），反相，回扫，Sepic |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 1.22 V ~ 42 V |
| 输入电压： | 2.5 V ~ 22 V |
| PWM 型： | 电流模式 |
| 频率 - 开关： | 200kHz ~ 2.5MHz |
| 电流 - 输出： | 3.3A |
| 同步整流器： | 无 |
| 工作温度： | -40°C ~ 125°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 16-TFSOP（0.118"，3.00mm 宽）裸露焊盘 |
| 包装： | 管件 |
| 供应商设备封装： | 16-MSOP，裸露焊盘 |
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LT3581
APPLICATIONS INFORMATION
T J =
f OSC =
where T J = Die Junction Temperature, T A = Ambient Tem-
perature, P TOTAL is the final result from the calculations
shown in Table 4, and θ JA is the thermal resistance from
the silicon junction to the ambient air.
The published (http://www.linear.com/designtools/pack-
aging/Linear_Technology_Thermal_Resistance_Table.
pdf) θ JA value is 43°C/W for the 4mm × 3mm 14-pin DFN
package and 45°C/W for the 16-lead MSOP package. In
practice, lower θ JA values are realizable if board layout is
performed with appropriate grounding (accounting for heat
sinking properties of the board) and other considerations
listed in the Layout Guidelines section. For instance, a
θ JA value of ~24°C/W was consistently achieved for both
MSE and DFN packages of the LT3581 (at V IN = 5V, V OUT =
12V, I OUT = 0.83A, f OSC = 2MHz) when board layout was
optimized as per the suggestions in the Board Layout
Guidelines section.
Junction Temperature Measurement
The duty cycle of the CLKOUT signal is linearly propor-
tional to die junction temperature, T J . To get a temperature
reading, measure the duty cycle of the CLKOUT signal and
use the following equation to approximate the junction
temperature:
DC CLKOUT – 35%
0 . 3 %
where DC CLKOUT is the CLKOUT duty cycle in % and T J
is the die junction temperature in °C. Although the actual
die temperature can deviate from the above equation by
±15°C, the relationship between change in CLKOUT duty
cycle and change in die temperature is well defined. Basi-
cally a 1% change in CLKOUT duty cycle corresponds to a
3.33°C change in die temperature. Note that the CLKOUT
pin is only meant to drive capacitive loads up to 50pF.
Thermal Lockout
A fault condition occurs when the die temperature exceeds
165°C (see Operation Section), and the part goes into
thermal lockout. The fault condition ceases when the die
temperature drops by ~5°C (nominal).
SWITCHING FREQUENCY
There are several considerations in selecting the operat-
ing frequency of the converter. The first is staying clear
of sensitive frequency bands, which cannot tolerate any
spectral noise. For example, in products incorporating RF
communications, the 455kHz IF frequency is sensitive to
any noise, therefore switching above 600kHz is desired.
Some communications have sensitivity to 1.1MHz and in
that case a 1.5MHz switching converter frequency may be
employed. The second consideration is the physical size
of the converter. As the operating frequency goes up, the
inductor and filter capacitors go down in value and size.
The tradeoff is efficiency, since the losses due to switch-
ing dynamics (see Thermal Considerations), Schottky
diode charge, and other capacitive loss terms increase
proportionally with frequency.
Oscillator Timing Resistor (R T )
The operating frequency of the LT3581 can be set by the
internal free-running oscillator. When the SYNC pin is driven
low (< 0.4V), the frequency of operation is set by a resistor
from the R T pin to ground. An internally trimmed timing
capacitor resides inside the IC. The oscillator frequency
is calculated using the following formula:
87 . 6
R T + 1
where f OSC is in MHz and R T is in k. Conversely, R T (in k)
can be calculated from the desired frequency (in MHz)
using:
R T =
87.6
f OSC
– 1
3581fa
18
For more information www.linear.com/LT3581
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LT3581EMSE-TRPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:3.3A Boost/Inverting DC/DC Converter with Fault Protection |
| LT3581HDE#PBF | 制造商:Linear Technology 功能描述:IC REG MULTI CONFIG ADJ 14DFN |
| LT3581HDE#TRPBF | 制造商:Linear Technology 功能描述:IC REG MULTI CONFIG ADJ 14DFN |
| LT3581IDE#PBF | 功能描述:IC REG MULTI CONFIG ADJ 14DFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 标准包装:2,500 系列:- 类型:降压（降压） 输出类型:固定 输出数:1 输出电压:1.2V，1.5V，1.8V，2.5V 输入电压:2.7 V ~ 20 V PWM 型:- 频率 - 开关:- 电流 - 输出:50mA 同步整流器:是 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:10-TFSOP，10-MSOP（0.118"，3.00mm 宽）裸露焊盘 包装:带卷 (TR) 供应商设备封装:10-MSOP 裸露焊盘 |
| LT3581IDE#TRPBF | 功能描述:IC REG MULTI CONFIG ADJ 14DFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 标准包装:2,500 系列:- 类型:降压（降压） 输出类型:固定 输出数:1 输出电压:1.2V，1.5V，1.8V，2.5V 输入电压:2.7 V ~ 20 V PWM 型:- 频率 - 开关:- 电流 - 输出:50mA 同步整流器:是 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:10-TFSOP，10-MSOP（0.118"，3.00mm 宽）裸露焊盘 包装:带卷 (TR) 供应商设备封装:10-MSOP 裸露焊盘 |
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