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| 型号： | 18448 |
| 英文描述： | Microprocessor Family CPU Thermal Management Application Note? 126KB (PDF) |
| 中文描述： | 微处理器系列CPU散热管理应用笔记？ 126KB（PDF格式） |
| 文件页数： | 8/10页 |
| 文件大小： | 126K |
| 代理商： | 18448 |
AMD
CPU Thermal Management
7
Table 4. Comparison of Electrical Parameters to
Analogous Thermal Parameters
Thermal capacitance is equal to the product of the spe-
cific heat (H) of the material used in the sample and the
mass (M) of the sample; it is the quantity of heat ab-
sorbed by the sample when its temperature rises 1
°C.
Therefore, if a sample absorbs a quantity of heat (Q)
when its temperature is increased from T1 to T2, the
thermal capacitance of the sample, expressed in watt-
seconds per °C, can be determined from the following
equation:
Figure 10 shows the electro-thermal circuit for a three
layer device. Thermal impedance, like electrical im-
pedance, is a complex variable because of the time
dependence associated with the thermal capacitance.
In this circuit, the thermal resistances closest to the
heat source are large because the cross section of the
semiconductor is small (all the heat flows through a
small area). Thermal resistance varies inversely with
cross sectional area (as shown in equation 3). Thermal
resistance becomes progressively smaller as distance
from the semiconductor increases.
Since thermal capacitance varies directly with both
specific heat and mass, the small mass of the semicon-
ductor causes the thermal capacitance to be smallest
at the heat source and to become pressively larger as
distance from the heat source increases. The final ther-
mal capacitance in the series is considered an infinite
capacitance, which is electrically equivalent to a short
across the end of the line.
R = x/KA
C = p c v
p = density
c = heat capacity
v = volume
Figure 10. Electrothermal Circuit
for a Three-Layer Device
To simplify the equation, assume a steady state condi-
tion where capacitance does not play a role. Thus, for
a three-layer device (die, epoxy, and package), total
thermal resistance equals three resistances in a series.
Consider a square heat source of side dimension a in
contact with a package of thickness x. For simplicity,
assume that the thermal spread angle of the material is
45°. Thus, the area is the truncated pyramid and theta
is calculated by the following equation:
Electrical
Resistance
R(Ohms)
Capacitance
C
Amps-sec/V
Voltage
VVolts
Current
IAmps
Conductivity
p
Ohms/cm2
Charge
qCoulomb
Thermal
Thermal resistance
q
°C/W
Thermal capacitance
CW-sec/°C
Temp. difference
T°C
Power dissipation
P
Watts
Thermal conductivity
KW/in-°C
Quantity of heat
Q
Calories
R2
V1
V2
–
P
---------------------
=
θ2
T1
T2
–
P
--------------------
=
C
Q
T2
T1
–
--------------------
=
P
C1
C2
C3
R1
R2
R3
ZeQ
P
R
die
R
epoxy
R
package
++
a
x
a
45
°
θ
1K
() xarea
d
∫
=
area
f x
()
=
APPENDIX
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| 1845E | Optoelectronic |
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| 1845H | Optoelectronic |
| 1847E | Optoelectronic |
| 1847G | Optoelectronic |
相关代理商/技术参数 |
参数描述 |
|---|---|
| 1844800000 | 制造商:Weidmuller 功能描述:CONN TERM BLOCKS 27 POS 5.08MM SLDR ST TH 10A - Bulk 制造商:Weidmuller 功能描述:LP3R 5.08/27/90 3.2SN OR |
| 1844808 | 功能描述:20 位 端接块 接头，公引脚，带罩（4 面） 0.100"（2.54mm） 90°，直角 通孔 制造商:phoenix contact 系列:COMBICON DMC 包装:带卷（TR） 零件状态:新产品 类型:接头，公引脚，带罩（4 面） 针脚数:20 每级针脚数:10 级别数:2 间距:0.100"（2.54mm） 针座方向:90°，直角 插线入口:- 端子类型:焊接 安装类型:通孔 电流 - IEC:6A 电压 - IEC:160V 电流 - UL:6A 电压 - UL:150V 线规或范围 - AWG:- 线规或范围 -?mm2:- 颜色:黑 工作温度:- 触头配接表面处理:金 特性:固定焊尾 标准包装:300 |
| 1844810000 | 制造商:Weidmuller 功能描述:CONN TERM BLOCKS 33 POS 5.08MM SLDR ST TH 10A - Bulk 制造商:Weidmuller 功能描述:LP3R 5.08/33/90 3.2SN OR |
| 1844811 | 功能描述:22 位 端接块 接头，公引脚，带罩（4 面） 0.100"（2.54mm） 90°，直角 通孔 制造商:phoenix contact 系列:COMBICON DMC 包装:带卷（TR） 零件状态:新产品 类型:接头，公引脚，带罩（4 面） 针脚数:22 每级针脚数:11 级别数:2 间距:0.100"（2.54mm） 针座方向:90°，直角 插线入口:- 端子类型:焊接 安装类型:通孔 电流 - IEC:6A 电压 - IEC:160V 电流 - UL:6A 电压 - UL:150V 线规或范围 - AWG:- 线规或范围 -?mm2:- 颜色:黑 工作温度:- 触头配接表面处理:金 特性:固定焊尾 标准包装:300 |
| 1844820000 | 制造商:Weidmuller 功能描述:CONN TERM BLOCKS 36 POS 5.08MM SLDR ST TH 10A - Bulk 制造商:Weidmuller 功能描述:LP3R 5.08/36/90 3.2SN OR |
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