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LM76003-Q1: Webench Simulator does not plot Steady-State, Input/Load Transient for a LM76003-Q design

Part Number: LM76003-Q1

Hello,

I cannot plot the Load Transient, Steady State and Input Transient in a LM76003-Q1 design. I can only see the Bode Plot.

It is a step-down, Vinput: 21V-49V, Voutput: 12V, Io = 3,5A.

The Webench reports enough MF = 48º and everything seems to be ok. I attach the report for your checking.

I have changed the suggested inductor to another one that has practically the same parameters.

Now is 447709220 but remains the same value, 22uH. I've got this one available, that's the reason.

On the other hand, the output capacitance is as follows:

Cout = 22uF, ESR = 2mOhm.

GRM32ER71E226ME15L.

Which at 12V has a derating of 61,5%, so, we really have 8,47uF.

Therefore, 8,47uF x 5 = 42,4uF, which seems to be enough (MF = 48º) to be stable according to the simulator.

With that being said, I'd expect to see the simulations running and see the plots but I always get an error message.

Also, according to the numbers and formulas in datasheet, Cout > = 59,4uF which is a higher than the one suggested by the Webench Simulator (close to 40uF when selecting Ceramics only).

I detail parameters used to get 59,4uF. Ripple = 30%, DVo = 4% of 12V = 0,48V, Eff = 0,95, Fsw = 400kHz

Could you please, help with this Webench error and with mismatching Cout values (Webench and datasheet)?

WBDesign107.pdf

Regards,