Datasheet

Electrical Characteristics
S12XS Family Reference Manual, Rev. 1.13
664 Freescale Semiconductor
Table A-5. Thermal Package Characteristics (9S12XS256)
1
1
The values for thermal resistance are achieved by package simulations
Num C Rating Symbol Min Typ Max Unit
LQFP 112
1 D Thermal resistance LQFP 112, single sided PCB
2
2
Junction to ambient thermal resistance, θ
JA
was simulated to be equivalent to the JEDEC specification JESD51-2 in a
horizontal configuration in natural convection.
θ
JA
——62°C/W
2 D Thermal resistance LQFP 112, double sided PCB
with 2 internal planes
3
3
Junction to ambient thermal resistance, θ
JA
was simulated to be equivalent to the JEDEC specification JESD51-7 in a
horizontal configuration in natural convection.
θ
JA
——51°C/W
3 D Junction to Board LQFP 112 θ
JB
——39°C/W
4 D Junction to Case LQFP 112
4
θ
JC
——16°C/W
5 D Junction to Package Top LQFP 112
5
Ψ
JT
—— 3°C/W
QFP 80
6 D Thermal resistance QFP 80, single sided PCB
2
θ
JA
——57°C/W
7 D Thermal resistance QFP 80, double sided PCB
with 2 internal planes
3
θ
JA
——45°C/W
8 D Junction to Board QFP 80 θ
JB
——29°C/W
9 D Junction to Case QFP 80
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.
θ
JC
——20°C/W
10 D Junction to Package Top QFP 80
5
5
Thermal characterization parameter Ψ
JT
is the “resistance” from junction to reference point thermocouple on top center of the
case as defined in JESD51-2. Ψ
JT
is a useful value to use to estimate junction temperature in a steady state customer
enviroment.
Ψ
JT
—— 5°C/W
LQFP 64
11 D Thermal resistance LQFP 64, single sided PCB
2
θ
JA
——68°C/W
12 D Thermal resistance LQFP 64, double sided PCB
with 2 internal planes
3
θ
JA
——50°C/W
13 D Junction to Board LQFP 64 θ
JB
——32°C/W
14 D Junction to Case LQFP 64
4
θ
JC
——15°C/W
15 D Junction to Package Top LQFP 64
5
Ψ
JT
—— 3°C/W