Electrical characteristics
STM32F100x4, STM32F100x6, STM32F100x8, STM32F100xB
5.3.10
EMC characteristics
Susceptibility tests are performed on a sample basis during device characterization.
Functional EMS (Electromagnetic susceptibility)
While a simple application is executed on the device (toggling 2 LEDs through I/O ports). the
device is stressed by two electromagnetic events until a failure occurs. The failure is
indicated by the LEDs:
●
Electrostatic discharge (ESD) (positive and negative) is applied to all device pins until
a functional disturbance occurs. This test is compliant with the IEC 61000-4-2 standard.
●
FTB: A Burst of Fast Transient voltage (positive and negative) is applied to V and
DD
V
through a 100 pF capacitor, until a functional disturbance occurs. This test is
SS
compliant with the IEC 61000-4-4 standard.
A device reset allows normal operations to be resumed.
The test results are given in Table 29. They are based on the EMS levels and classes
defined in application note AN1709.
Table 29. EMS characteristics
Symbol
Parameter
Conditions
Level/Class
VDD 3.3 V, TA +25 °C,
Voltage limits to be applied on any I/O pin to fHCLK 24 MHz, LQFP100
VFESD
2B
induce a functional disturbance
package, conforms to
IEC 61000-4-2
VDD3.3 V, TA +25 °C,
fHCLK 24 MHz, LQFP100
package, conforms to
IEC 61000-4-4
Fast transient voltage burst limits to be
applied through 100 pF on VDD and VSS pins
to induce a functional disturbance
VEFTB
4A
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. It should be noted that good EMC
performance is highly dependent on the user application and the software in particular.
Therefore it is recommended that the user applies EMC software optimization and pre
qualification tests in relation with the EMC level requested for his application.
Software recommendations
The software flowchart 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
second. 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 (see application note AN1015).
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