MC9S08PT16 Datasheet, PDF (17/33 Pages) Freescale Semiconductor, Inc – MC9S08PT16

Rating
Operating temperature range T_A
(packaged)
Junction temperature range T_J
44-pin LQFP
θ_JA
32-pin LQFP
θ_JA
20-pin SOIC
θ_JA
20-pin TSSOP
θ_JA
16-pin TSSOP
θ_JA
44-pin LQFP
θ_JA
32-pin LQFP
θ_JA
20-pin SOIC
θ_JA
20-pin TSSOP
θ_JA
16-pin TSSOP
θ_JA
Table 8. Thermal characteristics
Symbol
Value
T_L to T_H -40 to 105
-40 to 150
Thermal resistance single-layer board
76
88
82
116
130
Thermal resistance four-layer board
54
59
54
76
87
Thermal specifications
Unit
°C
°C
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
The average chip-junction temperature (T_J) in °C can be obtained from:
T_J = T_A + (P_D × θ_JA)
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 the equations above for K gives:
K = P_D × (T_A + 273 °C) + θ_JA × (P_D)²
where K is a constant pertaining to the particular part. K can be determined by measuring
P_D (at equilibrium) for an known T_A. Using this value of K, the values of P_D and T_J can
be obtained by solving the above equations iteratively for any value of T_A.
MC9S08PT16 Series Data Sheet, Rev. 1, 7/4/2012.
Freescale Semiconductor, Inc.
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