参数资料
| 型号： | SOUNDBITE |
| 厂商： | Freescale Semiconductor |
| 文件页数： | 63/68页 |
| 文件大小： | 0K |
| 描述： | BOARD DEMO AUDIO DEVELOPMENT |
| 标准包装： | 1 |
| 系列： | Symphony™ soundBite |
| 主要目的： | 音频，音频处理 |
| 已用 IC / 零件： | DSPB56371 |
| 主要属性： | 最高 8 通道数字音频 |
| 次要属性： | USB、I2C、SPI 接口 |
| 已供物品： | 板，缆线，CD |
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Design Considerations
20
Design Considerations
20.1 Thermal Design Considerations
An estimation of the chip junction temperature, T J , in ° C can be obtained from the following equation:
T J = T A + ( P D × R θ JA )
Eqn. 4
Where:
T A =ambient temperature ° C
R qJA =package junction-to-ambient thermal resistance ° C/W
P D =power dissipation in package W
Historically, thermal resistance has been expressed as the sum of a junction-to-case thermal resistance and
a case-to-ambient thermal resistance.
R θ JA = R θ JC + R θ CA
Eqn. 5
Where:
R θ JA =package junction-to-ambient thermal resistance °C/W
R θ JC =package junction-to-case thermal resistance °C/W
R θ CA =package case-to-ambient thermal resistance °C/W
R θ JC is device-related and cannot be influenced by the user. The user controls the thermal environment to
change the case-to-ambient thermal resistance, R θ CA . For example, the user can change the air flow around
the device, add a heat sink, change the mounting arrangement on the printed circuit board (PCB), or
otherwise change the thermal dissipation capability of the area surrounding the device on a PCB. This
model is most useful for ceramic packages with heat sinks; some 90% of the heat flow is dissipated through
the case to the heat sink and out to the ambient environment. For ceramic packages, in situations where
the heat flow is split between a path to the case and an alternate path through the PCB, analysis of the
device thermal performance may need the additional modeling capability of a system level thermal
simulation tool.
The thermal performance of plastic packages is more dependent on the temperature of the PCB to which
the package is mounted. Again, if the estimations obtained from R θ JA do not satisfactorily answer whether
the thermal performance is adequate, a system level model may be appropriate.
A complicating factor is the existence of three common ways for determining the junction-to-case thermal
resistance in plastic packages.
? To minimize temperature variation across the surface, the thermal resistance is measured from the
junction to the outside surface of the package (case) closest to the chip mounting area when that
surface has a proper heat sink.
? To define a value approximately equal to a junction-to-board thermal resistance, the thermal
resistance is measured from the junction to where the leads are attached to the case.
? If the temperature of the package case (T T ) is determined by a thermocouple, the thermal
resistance is computed using the value obtained by the equation
(T J – T T )/P D .
DSP56371 Data Sheet, Rev. 4.1
Freescale Semiconductor
63
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相关代理商/技术参数 |
参数描述 |
|---|---|
| SOURCE INSPECTION | 制造商:Vishay Dale 功能描述:FACTORY INSPECTION |
| SOURCE INSPECTION CHARGE | 制造商:Leach International Corporation 功能描述:SUB MINIATURE - Virtual or Non-Physical Inventory (Software & Literature) |
| SOURCEINSPECTION/SG1549Y-12824 | 制造商:Microsemi Corporation 功能描述:CURRENT SENSE LATCH - Bulk |
| SOVEREIGN 10-300 | 制造商:Fane International 功能描述:Sovereign Series 10" Professional Audio Woofer - 300W RMS |
| SOVEREIGN 12-200 | 制造商:Fane International 功能描述:Sovereign Series 12 Inch Prosound Woofer 200W |
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