SLUAAY9 August 2024 TPS543320 , TPS543620 , TPS543820
This application note introduces how to utilize an AC coupled circuit to keep the signal from a clock generator within the absolute voltage ratings for the SYNC/FSEL pin to avoid damaging the DC/DC converter. This circuit is designed to adhere to the synchronization high-level input voltage threshold of 1.8V for the device and the absolute minimum input voltage on the SYNC/FSEL pin of -0.3V. Acceptable component values are discussed and results of a typical application circuit are shown. For a standard clock voltage of 3.3V, we found that an R1 value of 1.1kΩ, C1 value from 1nF to 100nF and a BAT54W satisfied the SYNC/FSEL pin requirements for the TPS543620.