Introduction

Electronic equipment using microcontrollers and microprocessors is more and more often exposed to a harsh electromagnetic

environment. The designs become more complex and more integrated. The increasing number of interfaces through which the

MCUs and MPUs interact with the external world multiply the paths for the interference to reach them. This raises plenty of

design challenges in building robust equipment.

Among other electromagnetic disturbances, an electrostatic discharge (ESD) is one of the most harmful effects that designers

must consider since the beginning of the design process.

STM32 MCU and MPU devices embed protection against ESD events during the device handling and assembly. Their ESD

immunity is characterized according to ANSI/JEDEC standards and specified in their datasheet. The equipment manufacturing

process must prevent them from any ESD stress exceeding that specification.

The electronic equipment design measures that allow protecting sensitive parts such as MCUs and MPUs include casing,

shielding, wiring, filtering, PCB routing, and adequate protection components to dissipate ESD stress and keep it far from the

sensitive parts. The MCU or MPU internal ESD protection then absorbs the remaining stress that might reach the device.

EMC-aware design of an electronic equipment considers all paths for the ESD stress to reach components and provides an

appropriate protective solution to each of them.

ESD protection of STM32 MCUs and MPUs

AN5612

Application note

AN5612 - Rev 1 - June 2022

For further information contact your local STMicroelectronics sales office.

www.st.com

1 General information

This document applies to Arm

-based MCUs and MPUs.

Note: Arm is a registered trademark of Arm Limited (or its subsidiaries) in the US and/or elsewhere.

Table 1. Glossary of terms

Term Developed form

ANSI American national standards institute

BLE

Bluetooth

Low Energy

CDM Charged-device model

CSI Camera serial interface

DSI Display serial interface

D-PHY Physical layer option set by MIPI alliance

ECMF EMI/RFI common mode filter

EMIF Electromagnetic interference filter

ESDA ESD association

ESD Electrostatic discharge

GPIO General purpose input/output

JEDEC Joint electron device engineering council

JTAG Joint test action group

HBM Human body model

IEC International electrotechnical commission

MM Machine model

MIPI Mobile industry processor interface

MOV Metal oxide varistor

NFC Near-field communication

PCB Printed circuit board

SMC Surface mounted component

SMPS Switch mode power supply

SWD Serial wire debug

TVS Transient voltage suppressor

VBR Voltage breakdown

Table 2. Reference documents

Reference number

Document title

[1] EMC design guide for STM8, STM32 and Legacy MCUs, AN1709

[2] ESD considerations for touch sensing applications on MCUs, AN3960

Table 3. Complementary literature available on www.st.com