The ESDL031-1BF4 is an ESD (electrostatic discharge) suppressor from STMicroelectronics that serves as a protective device to guard against electrostatic discharge and transient surge events. It is constructed with a combination of TVS (transient-voltage-suppressor) diodes, DFD (data-field-dependent) protection, and filtering. The TVS diodes provide fast response time protection, while the DFD protection helps to protect data lines such as I2C and USB from transients. Finally, the built-in filter helps to prevent high frequency noise from entering the system while allowing signals to pass through with minimal attenuation. This device is suitable for use in a wide range of applications, including automotive, consumer, mobile, and industrial systems.