Keeping ESD out is best accomplished by protection diodes – sadly, many of not most of them have high capacities which cause problems with fast signals. The ESD8472, also known as SZESD8472MUT5G, works around that problem.

It is based on the concept of the antiparalell diode – think of the part like of a combination of two Zener diodes connected head to head. According to the datasheet, the breakdown voltage lies between 7 and 12V, which means that the part can also be used with 5V signaling systems.

Our part differs from normal diodes in that it has an extremely low capacitance of but 0.2 pF. One stand-out feature of the SZESD8472MUT5G is the constancy of the capacitance over the entire voltage range – as shown in the figure, no significant changes take place over the entire voltage span.

An extremely constant U-C curve makes compensating diode effects easy

ON Semiconductor greatly simplifies placing of the part by using an ultra-tiny 0201DNS housing, which means that next to no space is needed on your PCB. Sadly, this also comes with a cost – soldering the ESD8472 by hand is almost impossible.

The part is obviously intended for RF applications. It takes but one cursory look at the datasheet hosted here to find a wide variety of diagrams related to high frequency applications.

Author: Tam Hanna
Published: March 12, 2021