4170G Aavid Thermalloy, 4170G Datasheet - Page 9

• Manufacturer Part Number: 4170G
• Description: ALUMINUM OXIDE INSULATOR
• Manufacturer: Aavid Thermalloy
• Type: Transistor Insulatorr

Specifications of 4170G

• Features: High Frequency Usage
• Shape: Rectangular
• Length: 0.760" (19.30mm)
• Width: 0.550" (13.97mm)
• Height: 0.070" (1.78mm)
• For Use With/related Products: TO-220
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Color: -
• Diameter - Inside: -
• Diameter - Outside: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 33879

The basic equation for heat transfer or power dissipation may be stated as follows:
Where:
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.
FIGURE 1
Where:
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 =
Semiconductor case
www.aavidthermalloy.com
R θJC + R θCS + R θSA
(cooler/dissipator)
Mounting surface
(usually stated by manufacturer of semiconductor device).
(heat source)
and the surface on which it is mounted in °C per watt.
Δ T
ΣR θ
Junction
Interface
T J –T A
P
R
D
θJC
R
θCS
T
J
T
C
T
S
surface to ambient, equation (3)
AMERICA
to ambient, equation (1)
Heat flow path junction
to ambient equation (2)
EUROPE
Heat flow path mounting
Heat flow path case
R
θSA
Italy Tel: [phone] email: [e-mail]
United Kingdom Tel: [phone] email: [e-mail]
USA Tel: [phone] email: [e-mail]
P D =
P
D
Atmosphere
R θCS + R θSA
or ambient
T
T
T C –T A
A
A
The common practice is to represent the system with
a network of resistances in series as shown in Figure 2.
FIGURE 2
T J
R θJC
ASIA
P D =
How To Select a Heat Sink
Singapore Tel: [phone] email: [e-mail]
Taiwan Tel: [phone] email: [e-mail]
T S –T A
T C
R θSA
R θCS
T S
R θSA
T A
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