MC68LC040RC25A Freescale Semiconductor, MC68LC040RC25A Datasheet - Page 347

• Manufacturer Part Number: MC68LC040RC25A
• Description: IC MPU 32BIT 25MHZ 179-PGA
• Manufacturer: Freescale Semiconductor

Specifications of MC68LC040RC25A

• Processor Type: M680x0 32-Bit
• Speed: 25MHz
• Voltage: 5V
• Mounting Type: Surface Mount
• Package / Case: 179-PGA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -

Reviewing the maximum ambient operating temperatures illustrates that using an all small
buffer configuration of the MC68040 with a relatively small amount of airflow (100 LFM)
achieves a 0–70 C ambient operating temperature. However, depending on the output
buffer configuration and available forced-air cooling, additional thermal management
techniques may be required.
11.9.3 With Heat Sink
The designer must consider many factors in choosing a heat sink: heat-sink size and
composition, method of attachment, and choice of a dry or wet (i.e., thermal grease)
connection. The following paragraphs discuss the relationship of these decisions to the
thermal performance of the design noticed during experimentation.
The heat-sink size is one of the most significant parameters to consider in the selection of
a heat sink. Obviously a larger heat sink provides better cooling. Under forced-air
conditions as low as 100 LFM, the difference between the
less). This difference continues to decrease as the forced airflow increases.
The area of this example heat-sink base perimeter is 1.8"
The heat-sink used a pin-fin (i.e., bed-of-nails) design composed of aluminum alloy. Figure
11-32 illustrates the heat sink, which can be obtained through Thermalloy, Inc.
MOTOROLA
MHz
20
25
33
20
25
33
20
25
33
20
25
33
20
25
33
Table 11-4. Thermal Parameters with Forced Airflow and No Heat Sink
Airflow Velocity
Thermal Mgmt.
Technique
1000 LFM
100 LFM
250 LFM
500 LFM
750 LFM
Freescale Semiconductor, Inc.
for the MC68LC040 and MC68EC040
For More Information On This Product,
6.3W
6.3W
6.3W
6.3W
6.3W
4 W
5 W
4 W
5 W
4 W
5 W
4 W
5 W
4 W
5 W
P
D
Defined Parameters
Go to: www.freescale.com
M68040 USER’S MANUAL
110 C
110 C
110 C
110 C
110 C
T
J
3 C/W
3 C/W
3 C/W
3 C/W
3 C/W
JC
Measured
12.7 C/W
9.9 C/W
9.5 C/W
9.3 C/W
11 C/W
JA
CA
1.8", with a height of 0.65".
is very small (0.4 C/W or
9.7 C/W
6.9 C/W
6.5 C/W
6.3 C/W
8 C/W
CA
Calculated
91.1 C
91.1 C
91.1 C
91.1 C
91.1 C
98 C
95 C
98 C
95 C
98 C
95 C
98 C
95 C
98 C
95 C
T
C
40.70 C
47.63 C
50.15 C
51.41 C
59.2 C
46.5 C
29.9 C
70.4 C
60.5 C
62.5 C
72.8 C
63.5 C
66 C
55 C
72 C
11-19
T
A