MC68HC000FN16 Freescale Semiconductor, MC68HC000FN16 Datasheet - Page 142

• Manufacturer Part Number: MC68HC000FN16
• Description: IC MPU 32BIT 16MHZ 68-PLCC
• Manufacturer: Freescale Semiconductor

Specifications of MC68HC000FN16

• Processor Type: M680x0 32-Bit
• Speed: 16MHz
• Voltage: 3.3V, 5V
• Mounting Type: Surface Mount
• Package / Case: 68-PLCC
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Features: -

10.3 POWER CONSIDERATIONS
where:
For most applications, P I/O <P INT and can be neglected.
Solving Equations (1) and (2) for K gives:
where K is a constant pertaining to the particular part. K can be determined from equation
(3) by measuring P D (at thermal equilibrium) for a known T A . Using this value of K, the
values of P D and T J can be obtained by solving Equations (1) and (2) iteratively for any
value of T A .
The curve shown in Figure 10-1 gives the graphic solution to the above equations for the
specified power dissipation of 1.5 W over the ambient temperature range of -55 C to 125
surrounding the device. Lower values of J A cause the curve to shift downward slightly; for
instance, for J A of 40 /W, the curve is just below 1.4 W at 25 C.
package (case) surface ( J C ) and from the case to the outside ambient air ( C A ). These
terms are related by the equation:
dependent and can be minimized by such thermal management techniques as heat sinks,
ambient air cooling, and thermal convection. Thus, good thermal management on the part
of the user can significantly reduce
Substitution of J C for
temperature.
10-2
The average die-junction temperature, T J , in C can be obtained from:
An appropriate relationship between P D and T J (if P I/O is neglected) is:
The total thermal resistance of a package ( J A ) can be separated into two components,
J C and C A , representing the barrier to heat flow from the semiconductor junction to the
J C is device related and cannot be influenced by the user. However, C A is user
C using a maximum J A of 45 C/W. Ambient temperature is that of the still air
T J = T A +(P D • J A )
T A
P D
P INT
P I/O
P D = K (T J + 273 C)
K = P D • (T A + 273 C) + JA • P D
J A
J A = J C + C A
= Ambient Temperature, C
= Package Thermal Resistance, Junction-to-Ambient, C/W
= P INT + P I/O
= I CC x V CC , Watts — Chip Internal Power
= Power Dissipation on Input and Output Pins — User Determined
M68000 8-/16-/32-BIT MICROPROCESSORS USER'S MANUAL
Freescale Semiconductor, Inc.
J A in equation 1 results in a lower semiconductor junction
For More Information On This Product,
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2
C A so that
J A approximately equals ; J C .
MOTOROLA
(1)
(2)
(3)
(4)