MC9S08DZ60MLF Datasheet, PDF (371/416 Pages) Freescale Semiconductor, Inc – MC9S08DZ60 Series Features

Appendix A Electrical Characteristics
Table A-3. Thermal Characteristics
Num C
Rating
Symbol
Value
Unit
Temp.
Code
1
D
Operating temperature range (packaged)
–40 to 125
M
T_A
–40 to 105
°C
V
–40 to 85
C
2
T _{Maximum Junction Temperature}¹
T_J
135
°C
—
3
D _{Thermal resistance}²
Single-layer board
64-pin LQFP
θ_JA
69
°C/W
48-pin LQFP
θ_JA
75
°C/W
32-pin LQFP
θ_JA
80
°C/W
Four-Layer board
64-pin LQFP
θ_JA
51
°C/W
48-pin LQFP
θ_JA
51
°C/W
32-pin LQFP
θ_JA
52
°C/W
1 _{Junction temperature is a function of die size, on-chip power dissipation, package thermal resistance, mounting site}
(board) temperature, ambient temperature, air flow, power dissipation of other components on the board, and board
thermal resistance.
2 _{Junction to Ambient Natural Convection}
The average chip-junction temperature (T_J) in °C can be obtained from:
T_J = T_A + (P_D × θ_JA)
Eqn. A-1
where:
T_A = Ambient temperature, °C
θ_JA = Package thermal resistance, junction-to-ambient, °C/W
P_D = P_int + P_I/O
P_int = I_DD × V_DD, Watts — chip internal power
P_I/O = Power dissipation on input and output pins — user determined
For most applications, P_I/O << P_int and can be neglected. An approximate relationship between P_D and T_J
(if P_I/O is neglected) is:
P_D = K ÷ (T_J + 273°C)
Solving equations 1 and 2 for K gives:
Eqn. A-2
K = P_D × (T_A + 273°C) + θ_JA × (P_D)²
Eqn. A-3
MC9S08DZ60 Series Data Sheet, Rev. 4
Freescale Semiconductor
371