STM32L051X6 Datasheet, PDF (77/127 Pages) STMicroelectronics – Access line ultra-low-power 32-bit MCU ARM-based Cortex-M0+, up to 64 KB Flash, 8 KB SRAM, 2 KB EEPROM, ADC

STM32L051x6 STM32L051x8
Electrical characteristics
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_DD and
V_SS through a 100 pF capacitor, until a functional disturbance occurs. This test is
compliant with the IEC 61000-4-4 standard.
A device reset allows normal operations to be resumed.
The test results are given in Table 51. They are based on the EMS levels and classes
defined in application note AN1709.
Table 51. EMS characteristics
Symbol
Parameter
Conditions
Level/
Class
V_FESD
V_EFTB
Voltage limits to be applied on any I/O pin to
induce a functional disturbance
V_DD 3.3 V, LQFP64, T_A +25 °C, 
f_HCLK 32 MHz
conforms to IEC 61000-4-2
3B
Fast transient voltage burst limits to be
applied through 100 pF on V_DD and V_SS
pins to induce a functional disturbance
V_DD3.3 V, LQFP64, T_A +25 °C, 
f_HCLK 32 MHz
4A
conforms to IEC 61000-4-4
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. 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
prequalification 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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