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Appendix A Electrical Characteristics
MC9S12XF - Family Reference Manual, Rev.1.19
1186
Freescale Semiconductor
Table A-5. Thermal Package Characteristics (MC9S12XF512) (1)
1. The values for thermal resistance are achieved by package simulations
Num
C
Rating
Symbol
Min
Typ
Max
Unit
LQFP144
1
D
Thermal resistance LQFP144, single sided PCB2
θJA
——
48
°C/W
2
D
Thermal resistance LQFP144, double sided PCB
with 2 internal planes3
θJA
——
40
°C/W
3
D
Junction to Board LQFP 144
θJB
——
28
°C/W
4
D
Junction to Case LQFP 1444
θJC
——
9
°C/W
5
D
Junction to Package Top LQFP1445
ΨJT
——
2
°C/W
LQFP112
6
D
Thermal resistance LQFP112, single sided PCB(2)
2. Junction to ambient thermal resistance,
θJA was simulated to be equivalent to the JEDEC specication JESD51-2 in a
horizontal conguration in natural convection.
θJA
——
49
°C/W
7
D
Thermal resistance LQFP112, double sided PCB
with 2 internal planes(3)
3. Junction to ambient thermal resistance,
θJA was simulated to be equivalent to the JEDEC specication JESD51-7 in a
horizontal conguration in natural convection.
θJA
——
40
°C/W
8
D
Junction to Board LQFP112
θJB
——
28
°C/W
9
D
Junction to Case LQFP1124
θJC
——
9
°C/W
10
D
Junction to Package Top LQFP1125
ΨJT
——
2
°C/W
LQFP64
11
D
Thermal resistance LQFP 64, single sided PCB2
θJA
——
62
°C/W
12
D
Thermal resistance LQFP 64, double sided PCB
with 2 internal planes3
θJA
——
44
°C/W
13
D
Junction to Board LQFP 64
θJB
——
27
°C/W
14
D
Junction to Case LQFP 64(4)
4. Junction to case thermal resistance was simulated to be equivalent to the measured values using the cold plate technique with
the cold plate temperature used as the “case” temperature. This basic cold plate measurement technique is described by MIL-
STD 883D, Method 1012.1. This is the correct thermal metric to use to calculate thermal performance when the package is
being used with a heat sink.
θJC
——
10
°C/W
15
D
Junction to Package Top LQFP 64(5)
5. Thermal characterization parameter
ΨJT is the “resistance” from junction to reference point thermocouple on top center of the
case as dened in JESD51-2.
ΨJT is a useful value to use to estimate junction temperature in a steady state customer
enviroment.
ΨJT
——
2
°C/W