MC9S08QG8_09 Datasheet, PDF (268/314 Pages) Freescale Semiconductor, Inc – HCS08 Microcontrollers

Appendix A Electrical Characteristics
A.3 Thermal Characteristics
This section provides information about operating temperature range, power dissipation, and package
thermal resistance. Power dissipation on I/O pins is usually small compared to the power dissipation in
on-chip logic and voltage regulator circuits, and it is user-determined rather than being controlled by the
MCU design. To take P_I/O into account in power calculations, determine the difference between actual pin
voltage and V_SS or V_DD and multiply by the pin current for each I/O pin. Except in cases of unusually high
pin current (heavy loads), the difference between pin voltage and V_SS or V_DD will be very small.
Table A-2. Thermal Characteristics
Rating
Operating temperature range (packaged)
C
M
Thermal resistance
Single-layer board
8-pin PDIP
8-pin NB SOIC
8-pin DFN
16-pin PDIP
16-pin TSSOP
16-pin QFN
24-pin QFN
Thermal resistance
Four-layer board
8-pin PDIP
8-pin NB SOIC
8-pin DFN
16-pin PDIP
16-pin TSSOP
16-pin QFN
24-pin QFN
Symbol
T_A
θ_JA
θ_JA
Value
Unit
T_L to T_H
–40 to 85
°C
–40 to 125
113
150
179
78
°C/W
133
132
125
72
87
41
53
°C/W
86
36
44
The average chip-junction temperature (T_J) in °C can be obtained from:
where:
T_J = T_A + (P_D × θ_JA)
T_A = Ambient temperature, °C
θ_JA = Package thermal resistance, junction-to-ambient, °C/W
P_D = P_int + P_I/O
Eqn. A-1
MC9S08QG8 and MC9S08QG4 Data Sheet, Rev. 5
266
Freescale Semiconductor