Datasheet

STM8AF52/62xx, STM8AF51/61xx Electrical characteristics
Doc ID 14395 Rev 9 87/110
10.4 Thermal characteristics
In case the maximum chip junction temperature (T
Jmax
) specified in Ta ble 26: General
operating conditions is exceeded, the functionality of the device cannot be guaranteed.
T
Jmax
, in degrees Celsius, may be calculated using the following equation:
Equation 3
T
Jmax
= T
Amax
+ (P
Dmax
x Θ
JA
)
where:
T
Amax
is the maximum ambient temperature in ° C
Θ
JA
is the package junction-to-ambient thermal resistance in ° C/W
P
Dmax
is the sum of P
INTmax
and P
I/Omax
(P
Dmax
= P
INTmax
+ P
I/Omax
)
P
INTmax
is the product of I
DD
and V
DD
, expressed in Watts. This is the maximum chip
internal power.
P
I/Omax
represents the maximum power dissipation on output pins
where:
Equation 4
P
I/Omax
= Σ (V
OL
* I
OL
) + Σ((V
DD
- V
OH
) * I
OH
)
taking into account the actual V
OL
/ I
OL
and V
OH
/ I
OH
of the I/Os at low- and high-level in the
application.
10.4.1 Reference document
JESD51-2 integrated circuits thermal test method environment conditions - natural
convection (still air). Available from www.jedec.org.
Table 51. Thermal characteristics
(1)
1. Thermal resistances are based on JEDEC JESD51-2 with 4-layer PCB in a natural convection
environment.
Symbol Parameter Value Unit
Θ
JA
Thermal resistance junction-ambient
LQFP 80 - 14 x 14 mm
38 °C/W
Θ
JA
Thermal resistance junction-ambient
LQFP 64 - 10 x 10 mm
46 °C/W
Θ
JA
Thermal resistance junction-ambient
LQFP 48 - 7 x 7 mm
57 °C/W
Θ
JA
Thermal resistance junction-ambient
LQFP 32 - 7 x 7 mm
59 °C/W
Θ
JA
Thermal resistance junction-ambient
VFQFPN 32 - 5 x 5 mm
25 °C/W