dsp56824 Freescale Semiconductor, Inc, dsp56824 Datasheet - Page 59

• Manufacturer Part Number: dsp56824
• Description: 16-bit Digital Signal Processor
• Manufacturer: Freescale Semiconductor, Inc

As noted above, the junction-to-case thermal resistances quoted in this data sheet are determined using the
first definition. From a practical standpoint, that value is also suitable for determining the junction
temperature from a case thermocouple reading in forced convection environments. In natural convection,
using the junction-to-case thermal resistance to estimate junction temperature from a thermocouple reading
on the case of the package will estimate a junction temperature slightly hotter than actual. Hence, the new
thermal metric, Thermal Characterization Parameter, or
value gives a better estimate of the junction temperature in natural convection when using the surface
temperature of the package. Remember that surface temperature readings of packages are subject to
significant errors caused by inadequate attachment of the sensor to the surface and to errors caused by heat
loss to the sensor. The recommended technique is to attach a 40-gauge thermocouple wire and bead to the
top center of the package with thermally conductive epoxy.
•
Use the value obtained by the equation (T
case determined by a thermocouple.
Table 19 on page 20 contains the package thermal values for this chip.
Freescale Semiconductor, Inc.
For More Information On This Product,
DSP56824 Technical Data
Go to: www.freescale.com
NOTE:
J
– T
T
)/P
JT
D
, has been defined to be (T
where T
T
is the temperature of the package
Thermal Design Considerations
J
– T
T
)/P
D
. This
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