STM32F042X4 Datasheet, PDF (111/117 Pages) STMicroelectronics – Reset and power management

STM32F042x4 STM32F042x6
Package information
7.8
Thermal characteristics
The maximum chip junction temperature (T_Jmax) 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/Omax),
• 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_DDIOx – 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.
Table 74. Package thermal characteristics
Symbol
Parameter
Thermal resistance junction-ambient
LQFP48 - 7 mm x 7 mm
Thermal resistance junction-ambient
UFQFPN48 - 7 mm x 7 mm
Thermal resistance junction-ambient
WLCSP36 2.6 mm x 2.7 mm
Θ_JA
Thermal resistance junction-ambient
LQFP32 - 7 mm x 7 mm
Thermal resistance junction-ambient
UFQFPN32 - 5 mm x 5 mm
Thermal resistance junction-ambient
UFQFPN28 - 4 mm x 4 mm
Thermal resistance junction-ambient
TSSOP20 - 6.5 mm x 6.4 mm
Value
55
33
64
57
38
118
76
Unit
°C/W
7.8.1
7.8.2
Reference document
JESD51-2 Integrated Circuits Thermal Test Method Environment Conditions - Natural
Convection (Still Air). Available from www.jedec.org
Selecting the product temperature range
When ordering the microcontroller, the temperature range is specified in the ordering
information scheme shown in Section 8: Ordering information.
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