Datasheet

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STM32F070xB STM32F070x6 Package characteristics
86
7.2 Thermal characteristics
The maximum chip junction temperature (T
J
max) must never exceed the values given in
Table 21: General operating conditions.
The maximum chip-junction temperature, T
J
max, in degrees Celsius, may be calculated
using the following equation:
T
J
max = T
A
max + (P
D
max x Θ
JA
)
Where:
• T
A
max is the maximum ambient temperature in °C,
•Θ
JA
is the package junction-to-ambient thermal resistance, in °C/W,
• P
D
max is the sum of P
INT
max and P
I/O
max (P
D
max = P
INT
max + P
I/O
max),
• P
INT
max is the product of I
DD
and V
DD
, expressed in Watts. This is the maximum chip
internal power.
P
I/O
max represents the maximum power dissipation on output pins where:
P
I/O
max = 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.
7.2.1 Reference document
JESD51-2 Integrated Circuits Thermal Test Method Environment Conditions - Natural
Convection (Still Air). Available from www.jedec.org
Table 63. Package thermal characteristics
Symbol Parameter Value Unit
Θ
J
Thermal resistance junction-ambient
LQFP64 - 10 mm x 10 mm
44
°C/W
Thermal resistance junction-ambient
LQFP48 - 7 mm x 7 mm
55
Thermal resistance junction-ambient
TSSOP20 - 6.5 mm x 6.4 mm
76
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