LMZ14202: LMZ14202

Hi Malek,

Is the Vout=3.3V? The Ron should be 63.5K for 400KHz freq.

B R

Andy

Hello Andy.

The output voltage waveform is attached. its between 3.2852 ~ 3.2876V. All information you need are in the images.

The circuit is suggested by TI WEBENCH.

The switching  frequency according to its datasheet is :

Fsw = 3.3/(1.3*10^(-10) * 54.9k) = 462.4 kHz. but FFT gives the switching frequency is about 630 kHz. Below image shows by using the time axis.

I am using FFT, but just to give the content frequencies in the wave directly.

Hi Malek,

Can you share your project? Please archive it according to (+) [FAQ] PSPICE-FOR-TI: How do I share PSpice for TI projects? - Simulation, hardware & system design tools forum - Simulation, hardware & system design tools - TI E2E support forums.

Thanks,
JC

Hello JZ Zhu,

Hope you are fine. 

The file is attached.

lmz14202_r0-2021-12-26T05-59.zip

Hi Malek,,

Thanks. We will review this.

-JC

Thank u in advance.

Hi Hattab:

you can change Ron to 85K, and check the I(V1:VIN) waveform so that you can read out the frequency.

Hello Daniel,

How did you get this value? 

I need to understand this point.

Because I have a board and I want to match the simulation results with spectrum analyzer results.

HI Malek:

based on the spice model, Ton=1.4745*1.3*10^-10*Ron/Vin, you can read out through the spice mode. the datasheet desire the silicon Ton is 1.3*10^-10*Ron/Vin which is the actually result . so there is a ratio of 1.4745 in it. 

I don't know why there is a ratio in the model, if  the simulation frequency match the board, you FFT analysis will be close.

Thanks

Yes, you are right.

Will figure out why this factor is used in the spice model.

Thank you very much Daniel. You are helpful.