101800F00000G Aavid Thermalloy, 101800F00000G Datasheet - Page 9
Manufacturer Part Number
Specifications of 101800F00000G
Size / Dimension
2 oz Tube
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
The basic equation for heat transfer or power dissipation may be stated as follows:
P D = the power dissipated by the semiconductor device in watts.
ΔT = the temperature difference of driving potential which causes the flow of heat.
ΣR θ = the sum of the thermal resistances of the heat flow path across which ΔT exists.
The above relationship may be stated in the following forms:
The above equations are generally used to determine the required thermal resistance of the heat sink (R θSA ),
since the heat dissipation, maximum junction and/or case temperature, and ambient temperature are known or set.
Figure 1 indicates the location of the various heat
flow paths, temperatures and thermal resistances.
T J = the junction temperature in °C (maximum is usually stated by the manufacturer of the semiconductor device).
T C = case temperature of the semiconductor device in °C.
T S = temperature of the heat sink mounting surface in thermal contact with the semiconductor device in °C.
T A = ambient air temperature in °C.
How to select a heat sink
P D =
R θJC = thermal resistance from junction to case of the semiconductor device in °C per watt
R θCS = thermal resistance through the interface between the semiconductor device
R θSA = thermal resistance from mounting surface to ambient or thermal resistance of heat sink in °C per watt.
P D =
R θJC + R θCS + R θSA
(usually stated by manufacturer of semiconductor device).
and the surface on which it is mounted in °C per watt.
T J –T A
surface to ambient, equation (3)
to ambient, equation (1)
Heat flow path junction
to ambient equation (2)
Heat flow path mounting
Heat flow path case
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P D =
R θCS + R θSA
T C –T A
The common practice is to represent the system with
a network of resistances in series as shown in Figure 2.
P D =
How To Select a Heat Sink
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T S –T A