DSP56F803 Motorola Inc, DSP56F803 Datasheet - Page 44

• Manufacturer Part Number: DSP56F803
• Description: 16-bit Hybrid Controller
• Manufacturer: Motorola Inc

The thermal characterization parameter is measured per JESD51-2 specification using a 40-gauge type T
thermocouple epoxied to the top center of the package case. The thermocouple should be positioned so that
the thermocouple junction rests on the package. A small amount of epoxy is placed over the thermocouple
junction and over about 1mm of wire extending from the junction. The thermocouple wire is placed flat
against the package case to avoid measurement errors caused by cooling effects of the thermocouple wire.
When heat sink is used, the junction temperature is determined from a thermocouple inserted at the interface
between the case of the package and the interface material. A clearance slot or hole is normally required in
the heat sink. Minimizing the size of the clearance is important to minimize the change in thermal
performance caused by removing part of the thermal interface to the heat sink. Because of the experimental
difficulties with this technique, many engineers measure the heat sink temperature and then back-calculate
the case temperature using a separate measurement of the thermal resistance of the interface. From this case
temperature, the junction temperature is determined from the junction-to-case thermal resistance.
44
•
Use the value obtained by the equation (T
case determined by a thermocouple.
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
J
– T
T
)/P
D
where T
T
is the temperature of the package
56F803 Technical Data