FAQs from Rohde & Schwarz

HMC804x: Frequency of switching regulator


Can you please let us know where the switching frequency of the HMC804x family is located?
We observe signals at about 80 kHz and want to be sure if it comes from the PSU or not.


The unit uses two stages. The first switching regulator works between 100 and 200 kHz while the second one works at about 250 kHz. In this respect, the observation at 80 kHz is unusual - another cause is very likely here.
The switching frequency of the device is adjusted depending on the load to improve efficiency.