ST STM32F103x6 Manual page 52

Package characteristics
6.1 Thermal characteristics
The average chip-junction temperature, T
following equation:
Where:
is the Ambient Temperature in ° C,
T
A
Θ
JA
P is the sum of P
D
P
INT
P represents the Power Dissipation on Input and Output Pins;
I/O
Most of the time for the application P
may be significant if the device is configured to drive continuously external modules and/or
memories.
An approximate relationship between P
Therefore (solving equations 1 and 2):
where:
K is a constant for the particular part, which may be determined from equation (3) by
measuring P
may be obtained by solving equations (1) and (2) iteratively for any value of T
Table 46.
Symbol
Θ
JA
64/67
T
J
is the Package Junction-to-Ambient Thermal Resistance, in ° C/W,
and P
INT
is the product of I
DD
P
D
K = P
D
(at equilibrium) for a known T
D
Thermal characteristics
Thermal resistance junction-ambient
LFBGA100 - 10 x 10 mm / 0.5 mm pitch
Thermal resistance junction-ambient
LQFP100 - 14 x 14 mm / 0.5 mm pitch
Thermal Resistance Junction-Ambient
LQFP64 - 10 x 10 mm / 0.5 mm pitch
Thermal resistance junction-ambient
LQFP48 - 7 x 7 mm / 0.5 mm pitch
, in degrees Celsius, may be calculated using the
J
x Θ
= T + (P )
A D JA
(P = P + P
I/O D INT I/O
and V , expressed in Watts. This is the Chip Internal Power.
DD
< P and can be neglected. On the other hand, P
I/O INT
and T (if P
D J
= K / (T + 273 °C)
J
+ 273°C) + Θ
x (T
A JA
Using this value of K, the values of P
A.
Parameter
(1)
),
is neglected) is given by:
I/O
(2)
2
x P (3)
D
Value
41
46
45
55
STM32F103xx
I/O
and T
D J
.
A
Unit
°C/W