Datasheet
DS10969 Rev 5 199/204
STM32L475xx Package information
200
Example 1: High-performance application
Assuming the following application conditions:
Maximum ambient temperature T
Amax
= 82 °C (measured according to JESD51-2),
I
DDmax
= 50 mA, V
DD
= 3.5 V, maximum 20 I/Os used at the same time in output at low
level with I
OL
= 8 mA, V
OL
= 0.4 V and maximum 8 I/Os used at the same time in output
at low level with I
OL
= 20 mA, V
OL
= 1.3 V
P
INTmax
=
50 mA × 3.5 V= 175 mW
P
IOmax
=
20 × 8 mA × 0.4 V + 8 × 20 mA × 1.3 V = 272 mW
This gives: P
INTmax
= 175 mW and P
IOmax
= 272 mW:
P
Dmax
=
175
+
272 = 447 mW
Using the values obtained in Table 103 T
Jmax
is calculated as follows:
– For LQFP64, 45 °C/W
T
Jmax
= 82 °C + (45 °C/W × 447 mW) = 82 °C + 20.115 °C = 102.115 °C
This is within the range of the suffix 6 version parts (–40 < T
J
< 105 °C) see Section 8:
Ordering information.
In this case, parts must be ordered at least with the temperature range suffix 6 (see Part
numbering).
Note: With this given P
Dmax
we can find the T
Amax
allowed for a given device temperature range
(order code suffix 6 or 7).
Suffix 6: T
Amax
= T
Jmax
- (45°C/W × 447 mW) = 105-20.115 = 84.885 °C
Suffix 7: T
Amax
= T
Jmax
- (45°C/W × 447 mW) = 125-20.115 = 104.885 °C
Example 2: High-temperature application
Using the same rules, it is possible to address applications that run at high ambient
temperatures with a low dissipation, as long as junction temperature T
J
remains within the
specified range.
Assuming the following application conditions:
Maximum ambient temperature T
Amax
= 100 °C (measured according to JESD51-2),
I
DDmax
= 20 mA, V
DD
= 3.5 V, maximum 20 I/Os used at the same time in output at low
level with I
OL
= 8 mA, V
OL
= 0.4 V
P
INTmax
=
20 mA × 3.5 V= 70 mW
P
IOmax
=
20 × 8 mA × 0.4 V = 64 mW
This gives: P
INTmax
= 70 mW and P
IOmax
= 64 mW:
P
Dmax
=
70
+
64 = 134 mW
Thus: P
Dmax
= 134 mW
Using the values obtained in Table 103 T
Jmax
is calculated as follows:
– For LQFP64, 45 °C/W
T
Jmax
= 100 °C + (45 °C/W × 134 mW) = 100 °C + 6.03 °C = 106.03 °C
This is above the range of the suffix 6 version parts (–40 < T
J
< 105 °C).
In this case, parts must be ordered at least with the temperature range suffix 7 (see
Section 8: Ordering information) unless we reduce the power dissipation in order to be able
to use suffix 6 parts.
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