Varey the fsw of MP4423 / MPQ4423

Hello together,

I’d like to use the MP4423 and varey the switching frequency of it. Therefore, I added a circuit to the en/sync Pin which is switching in the desired range.
To confirm its function and the behaviour of the MP4423, I used the MPSmart v8 Tool of you - it offers the automotive variant (MPQ4423) of the chip for simulation.
Does the model include correct behavior for en/sync switching?
Everytime I start switching the EN Pin (ds says, start switching 2ms after output voltage is stable, which I do), the IC stops working in simulation and the output voltage will drop.

Hi florian.reosel,

Thank you for contacting the MPS Forum. I’m looking at your question and will work on getting you an answer soon.

Brendan Schoemehl
Field Applications Engineer
Monolithic Power Systems | MPS Now

The EN pin SYNC function does not work in the simulation, the simulation is meant for typical operation characterization, not for outside factors. The external frequency sync can be considered an external influence on the device and would not fall under typical use case operation for the simulation.

My suggestion is to try the external sync feature using one of our evaluation boards as this will also give you the best idea of how the device will operate in the real world and in your system.


Hi Brendan,

thank you for you reply! I expected something like that and ordered an eval board already. It should arrive in the next few days and I’ll do further examinations.
Thank you for your help, I’ll get in touch, if I need further information.