STM32WB55xx STM32WB35xx
Package information
7.5
Note:
Note:
Note:
Thermal characteristics
The maximum chip junction temperature (TJmax) must never exceed the values given in
Table 24: General operating conditions.
The maximum chip-junction temperature, TJ max, in degrees Celsius, can be calculated
using the equation:
TJ max = TA max + (PD max x ΘJA)
where:
 TA max is the maximum ambient temperature in °C,
 ΘJA is the package junction-to-ambient thermal resistance, in °C / W,
ï‚· PD max is the sum of PINT max and PI/O max (PD max = PINT max + PI/O max),
ï‚· PINT max is the product of IDD and VDD, expressed in Watt. This is the maximum chip
internal power.
PI/O max represents the maximum power dissipation on output pins:
 PI/O max = Σ (VOL × IOL) + Σ ((VDD – VOH) × IOH)
taking into account the actual VOL / IOL and VOH / IOH of the I/Os at low and high level in the
application.
When the SMPS is used, a portion of the power consumption is dissipated into the external
inductor, therefore reducing the chip power dissipation. This portion depends mainly on the
inductor ESR characteristics.
As the radiated RF power is quite low (< 4 mW), it is not necessary to remove it from the
chip power consumption.
RF characteristics (such as sensitivity, Tx power, consumption) are provided up to 85 °C.
Symbol
ΘJA
ΘJB
Table 106. Package thermal characteristics
Parameter
Value
Thermal resistance junction-ambient
UFQFPN48 - 7 mm x 7 mm
24.9
Thermal resistance junction-ambient
VFQFPN68 - 8 mm x 8 mm
47.0
Thermal resistance junction-ambient
WLCSP100 - 0.4 mm pitch
35.8
Thermal resistance junction-ambient
UFBGA129 - 0.5 mm pitch
41.5
Thermal resistance junction-board
UFQFPN48 - 7 mm x 7 mm
13.0
Thermal resistance junction-board
VFQFPN68 - 8 mm x 8 mm
36.1
Thermal resistance junction-board
WLCSP100 - 0.4 mm pitch
N/A
Thermal resistance junction-board
UFBGA129 - 0.5 mm pitch
16.2
Unit
°C/W
°C/W
DS11929 Rev 10
183/193
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