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参数资料
| 型号： | SME5434PCI-440 |
| 元件分类： | 微控制器/微处理器 |
| 英文描述： | 64-BIT, 440 MHz, RISC PROCESSOR, XMA |
| 封装： | 130 X 100 MM, 45 MM HEIGHT MODULE |
| 文件页数： | 13/30页 |
| 文件大小： | 393K |
| 代理商： | SME5434PCI-440 |
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SME5431PCI-360
SME5434PCI-440
Preliminary
360/440MHz CPU; 0.25 to 2 MB L2 cache; UPA64S, 66MHz PCI Interfaces
UltraSPARC IIi CPU Module
September 2001
Sun Microsystems, Inc
Two Step Approach to the Thermal Design
Step One determines the air ow requirements based on the CPU power dissipation and the thermal charac-
teristics of the CPU package and the surrounding heatsink assembly. The specications for the heatsink are
provided in the table "Heatsink-to-Air Thermal Resistance" on page 21.
Step Two verifies cooling effectiveness by measuring the heatsink or case temperature and calculating the
junction temperature. The junction temperature must not exceed the CPU specification. In addition, the lower
the junction temperature, the higher the system reliability. The CPU temperature must be calculated for a
range of loads and environmental conditions, using one of the temperature measuring methods described in
the following sections.
Temperature Estimating and Measuring Methods
The following methods can be used to measure the case temperature of the module and to estimate the air-
ow required to cool it.
Case Temperature Method
The relationship between case temperature and junction temperature is described in the following thermal
equation.
If Tc is known, then Tj can be calculated:
Tj = Tc + (Pd x
θjc)
There is good tracking between the case temperature and the heatsink temperature.
Heatsink Temperature Method (Preferred Method)
Measuring the heatsink temperature is sometimes easier than measuring the case temperature. This method
provides accurate results for most designs. If the heatsink temperature (Ts) is known then the following ther-
mal equation can be used to estimate the junction temperature.
Tj = Ts + [Pd (
θjc + θcs)]
Airow Cooling Estimate Method
The relationship between air temperature and junction temperature is described in the thermal equation:
Tj =
Ti + [Pd (
θjc + θcs + θsa)]
Determination of the inlet air temperature (Ti) and the “free-stream” air velocity is required in order to apply
the airow method. The table:"Heatsink-to-Air Thermal Resistance" on page 21 uses the air velocity direction
relative to the heatsink orientation to nd the thermal resistance between the heatsink and air (
θsi).
Note that the airow velocity can be measured using a velocity meter. Alternatively, it may be determined by
knowing the performance of the fan that is supplying the airow. Calculating the airow velocity is difcult.
It is subject to the interpretation of the term “free-stream.”
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相关代理商/技术参数 |
参数描述 |
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| SME6.3VB101M6X11LL | 制造商:未知厂家 制造商全称:未知厂家 功能描述:MINIATURE, GENERAL PURPOSE, SOLVENT PROOF |
| SME6.3VB102M10X12LL | 制造商:United Chemi-Con Inc 功能描述:Capacitor, Aluminium, 1mf, 6.3V, 20±% |
| SME6.3VB103M16X31LL | 功能描述:铝质电解电容器 - 带引线 10KuF 6.3V RoHS:否 制造商:Kemet 引线类型: 电容:220 uF 容差:20 % 电压额定值:25 V 工作温度范围: 端接类型:Radial 外壳直径:8 mm 外壳长度:11 mm 引线间隔:5 mm 产品:General Purpose Electrolytic Capacitors 封装:Bulk |
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