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参数资料
| 型号： | LMR10510YSDDEMO/NOPB |
| 厂商： | National Semiconductor |
| 文件页数： | 14/26页 |
| 文件大小： | 0K |
| 描述： | BOARD EVAL FOR LMR10510 |
| 标准包装： | 1 |
| 系列： | SIMPLE SWITCHER® |
| 主要目的： | DC/DC，步降 |
| 输出及类型： | 1，非隔离 |
| 输出电压： | 1.8V |
| 电流 - 输出： | 1A |
| 输入电压： | 3 V ~ 5.5 V |
| 稳压器拓扑结构： | 降压 |
| 频率 - 开关： | 3MHz |
| 板类型： | 完全填充 |
| 已供物品： | 板 |
| 已用 IC / 零件： | LMR10510 |
SNVS727B – OCTOBER 2011 – REVISED APRIL 2013
Thermal Definitions
T J = Chip junction temperature
T A = Ambient temperature
R θ JC = Thermal resistance from chip junction to device case
R θ JA = Thermal resistance from chip junction to ambient air
Heat in the LMR10510 due to internal power dissipation is removed through conduction and/or convection.
Conduction: Heat transfer occurs through cross sectional areas of material. Depending on the material, the
transfer of heat can be considered to have poor to good thermal conductivity properties (insulator vs. conductor).
Heat Transfer goes as:
Silicon → package → lead frame → PCB
Convection: Heat transfer is by means of airflow. This could be from a fan or natural convection. Natural
convection occurs when air currents rise from the hot device to cooler air.
Thermal impedance is defined as:
R T =
' T
Power
Thermal impedance from the silicon junction to the ambient air is defined as:
R T JA =
T J - T A
Power
The PCB size, weight of copper used to route traces and ground plane, and number of layers within the PCB can
greatly effect R θ JA . The type and number of thermal vias can also make a large difference in the thermal
impedance. Thermal vias are necessary in most applications. They conduct heat from the surface of the PCB to
the ground plane. Four to six thermal vias should be placed under the exposed pad to the ground plane if the
WSON package is used.
Thermal impedance also depends on the thermal properties of the application operating conditions (Vin, Vo, Io
etc), and the surrounding circuitry.
Silicon Junction Temperature Determination Method 1:
To accurately measure the silicon temperature for a given application, two methods can be used. The first
method requires the user to know the thermal impedance of the silicon junction to case temperature.
R θ JC is approximately 18°C/Watt for the 6-pin WSON package with the exposed pad. Knowing the internal
dissipation from the efficiency calculation given previously, and the case temperature, which can be empirically
measured on the bench we have:
R T JC =
T J - T C
Power
where T C is the temperature of the exposed pad and can be measured on the bottom side of the PCB.
Therefore:
T j = (R θ JC x P LOSS ) + T C
From the previous example:
T j = (R θ JC x P INTERNAL ) + T C
T j = 18°C/W x 0.149W + T C
The second method can give a very accurate silicon junction temperature.
14
Product Folder Links: LMR10510
Copyright ? 2011–2013, Texas Instruments Incorporated
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LMR10510YSDE/NOPB | 功能描述:直流/直流开关调节器 SIMPLE SWITCHER 5.5 Vin,1A SD Vltg Reg RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| LMR10510YSDX | 制造商:TI 制造商全称:Texas Instruments 功能描述:SIMPLE SWITCHER?? 5.5Vin, 1A Step-Down Voltage Regulator in SOT-23 and LLP |
| LMR10510YSDX/NOPB | 功能描述:直流/直流开关调节器 SIMPLE SWITCHER 5.5 Vin,1A SD Vltg Reg RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| LMR10515 | 制造商:TI 制造商全称:Texas Instruments 功能描述:SIMPLE SWITCHER? 5.5Vin, 1.5A Step-Down Voltage Regulator in SOT-23 and LLP |
| LMR10515XMF | 制造商:Texas Instruments 功能描述:BUCK, 1.5A, 5.5VIN 制造商:Texas Instruments 功能描述:BUCK, 1.5A, 5.5VIN; Primary Input Voltage:5.5V; No. of Outputs:1; Output Voltage:4.5V; Output Current:1.5A; Voltage Regulator Case Style:SOT-23; No. of Pins:5; Operating Temperature Min:-40C; Operating Temperature Max:125C; SVHC:No;RoHS Compliant: Yes |
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