DSP56301PW80B1 Freescale Semiconductor, DSP56301PW80B1 Datasheet - Page 103

• Manufacturer Part Number: DSP56301PW80B1
• Manufacturer: Freescale Semiconductor

Specifications of DSP56301PW80B1

• Device Core Size: 24b
• Format: Fixed Point
• Clock Freq (max): 80MHz
• Mips: 80
• Device Input Clock Speed: 80MHz
• Ram Size: 24KB
• Program Memory Size: Not RequiredKB
• Operating Supply Voltage (typ): 3.3V
• Operating Supply Voltage (min): 3V
• Operating Supply Voltage (max): 3.6V
• Operating Temp Range: -40C to 100C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 208
• Package Type: TQFP
• Lead Free Status / Rohs Status: Not Compliant

Design Considerations
4.1 Thermal Design Considerations
An estimate of the chip junction temperature, T
Where:
Historically, thermal resistance has been expressed as the sum of a junction-to-case thermal resistance and a case-
to-ambient thermal resistance, as in this equation:
Where:
R
the case-to-ambient thermal resistance, R
a heat sink, change the mounting arrangement on the printed circuit board (PCB) or otherwise change the thermal
dissipation capability of the area surrounding the device on a PCB. This model is most useful for ceramic packages
with heat sinks; some 90 percent of the heat flow is dissipated through the case to the heat sink and out to the
ambient environment. For ceramic packages, in situations where the heat flow is split between a path to the case
and an alternate path through the PCB, analysis of the device thermal performance may need the additional
modeling capability of a system-level thermal simulation tool.
The thermal performance of plastic packages is more dependent on the temperature of the PCB to which the
package is mounted. Again, if the estimates obtained from R
performance is adequate, a system-level model may be appropriate.
A complicating factor is the existence of three common ways to determine the junction-to-case thermal resistance
in plastic packages.
Freescale Semiconductor
θJC
T
R
P
R
R
R
•
•
A
D
is device-related and cannot be influenced by the user. The user controls the thermal environment to change
θJA
θJA
θJC
θCA
To minimize temperature variation across the surface, the thermal resistance is measured from the junction
to the outside surface of the package (case) closest to the chip mounting area when that surface has a
proper heat sink.
To define a value approximately equal to a junction-to-board thermal resistance, the thermal resistance is
measured from the junction to the point at which the leads attach to the case.
Equation 1:
Equation 2:
=
=
=
=
=
=
ambient temperature °C
package junction-to-ambient thermal resistance °C/W
power dissipation in package
package junction-to-ambient thermal resistance °C/W
package junction-to-case thermal resistance °C/W
package case-to-ambient thermal resistance °C/W
T
R
J
θ JA
=
T
=
A
R
+
θ JC
(
P
D
+
×
R
R
θ CA
θCA
DSP56301 Technical Data, Rev. 10
θ JA
)
. For example, the user can change the air flow around the device, add
J
, in °C can be obtained from this equation:
θJA
do not satisfactorily answer whether the thermal
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