mc68ec030 Freescale Semiconductor, Inc, mc68ec030 Datasheet - Page 21

• Manufacturer Part Number: mc68ec030
• Description: Second-generation 32-bit Enhanced Embedded Controller
• Manufacturer: Freescale Semiconductor, Inc

AC ELECTRICAL SPECIFICATION DEFINITIONS
M O T O R O L A
The total thermal resistance of a package ( JA ) can be separated into two components,
representing the barrier to heat flow from the semiconductor junction to the package (case) surface ( JC )
and from the case to the outside ambient air ( CA ). These terms are related by the equation:
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 CA so that
semiconductor junction temperature.
Values for thermal resistance presented in this document, unless estimated, were derived using the
procedure described in Motorola Reliability Report 7843, “Thermal Resistance Measurement Method for
MC68XX Microcomponent Devices,” and are provided for design purposes only. Thermal measurements
are complex and dependent on procedure and setup. User derived values for thermal resistance may
differ.
The AC specifications presented consist of output delays, input setup and hold times, and signal skew
times. All signals are specified relative to an appropriate edge of the clock and possibly to one or more
other signals.
The measurement of the AC specifications is defined by the waveforms shown in Figure 9. To test the
parameters guaranteed by Motorola, inputs must be driven to the voltage levels specified in Figure 9.
Outputs are specified with minimum and/or maximum limits, as appropriate, and are measured as shown in
Figure 9. Inputs are specified with minimum setup and hold times, and are measured as shown. Finally,
the measurement for signal-to-signal specifications is also shown.
Note that the testing levels used to verify conformance to the AC specifications does not affect the
guaranteed DC operation of the device as specified in the DC electrical specifications.
JC is device related and cannot be influenced by the user. However, CA is user dependent and can
JA approximately equals;
Freescale Semiconductor, Inc.
JC . Substitution of
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JA = JC + CA
JC for
JA in equation (1) results in a lower
JC and CA ,
(4)
2 1