Datasheet

Table Of Contents
Electrical characteristics STM32WLE5J8/JB/JC
100/135 DS13105 Rev 4
Designing hardened software to avoid noise problems
EMC characterization and optimization are performed at component level with a typical
application environment and simplified MCU software.
Note: Good EMC performance is highly dependent on the user application and the software in
particular.It is then recommended that the user applies EMC software optimization and
prequalification tests in relation with the EMC level requested for the application.
Software recommendations
The software flow must include the management of runaway conditions such as:
corrupted program counter
unexpected reset
critical data corruption (control registers)
Prequalification trials
Most of the common failures (unexpected reset and program counter corruption) can be
reproduced by manually forcing a low state on the NRST pin or the oscillator pins for 1 s.
To complete these trials, ESD stress can be applied directly on the device, over the range of
specification values. When unexpected behavior is detected, the software can be hardened
to prevent unrecoverable errors occurring. For more details, refer to the application note
Software techniques for improving microcontrollers EMC performance (AN1015).
Electromagnetic interference (EMI)
The electromagnetic field emitted by the device is monitored while a simple application is
executed (toggling two LEDs through the I/O ports). This emission test is compliant with the
IEC 61967-2 standard, that specifies the test board and the pin loading.
Table 62. EMS characteristics
Symbol Parameter Conditions Level/Class
V
FESD
Voltage limits to be applied on any I/O pin to
induce a functional disturbance
V
DD
= 3.3 V, T
A
= +25 °C, f
HCLK
= 48 MHz,
conforming to IEC 61000-4-2
2B
V
EFTB
Fast transient voltage burst limits to be
applied through 100 pF on VDD and VSS
pins to induce a functional disturbance
V
DD
= 3.3 V, T
A
= +25 °C, f
HCLK
= 48 MHz,
conforming to IEC 61000-4-4
5A