What is this Diode for?

[jonas8750]

Hello,

In the Reference Design Guide of the BC660K-GL could someone explain what is the purpose of the diode ?

If the MCU is 3.3V is this still needed?

Thanks
Regards

[fuguiwang-Q]

In the Reference Design Guide of the BC660K-GL could someone explain what is the purpose of the diode ?
Reply：Prevent leakage current.

If the MCU is 3.3V is this still needed?
Reply：yes，Need to set the uart port of BC660K voltage domain to 3.3V，The voltage domain settings are as follows: