
Electrical Specifications
Functional Operating Range
M68HC12B Family — Rev. 4.0
Technical Data
MOTOROLA
Electrical Specifications
467
19.3 Functional Operating Range
19.4 Thermal Characteristics
Rating
Symbol
Value
Unit
All devices in this document meet these operating
temperature ranges:
“C” temperature range
“V” temperature range
“M” temperature range
TA
TL to TH
40 to +85
40 to +105
40 to +125
°C
Operating voltage range
VDD
5.0
± 10%
V
Characteristic
Symbol
Value
Unit
Average junction temperature
TJ
TA + (PD × ΘJA)
°C
Ambient temperature
TA
User-determined
°C
Package thermal resistance (junction-to-ambient)
80-pin quad flat pack (QFP)
Θ
JA
76
°C/W
Total power dissipation(1)
1. This is an approximate value, neglecting PI/O.
PD
PINT + PI/O
or
W
Device internal power dissipation
PINT
IDD × VDD
W
I/O pin power dissipation(2)
2. For most applications, PI/O PINT and can be neglected.
PI/O
User-determined
W
A constant(3)
3. K is a constant pertaining to the device. Solve for K with a known TA and a measured PD (at equilibrium).
Use this value of K to solve for PD and TJ iteratively for any value of TA.
K
PD × (TA + 273 °C) +
Θ
JA × PD
2
W/
°C
K
TJ 273°C
+
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