Hello Ali,
I have sent you PCB file on 12/15, have you received it?
Thanks for sharing me the web link. It's a new application to me.
Could you share more application details? I don't know where is 'big capacitor' that you said. If you mean add a big Electrolytic Cap (E-cap) at TPS56837 output, please take care of it. Because the E-cap has high ESR and will introduce a low-frequency ESR-zero into loop, which may cause loop instability. If you have to use the high-ESR E-cap, please remove the Cff and add a small Cfb from FB-pin to GND (Cfb value cannot be large, try 100pF), like below.
And seems the product you shared supports adjustable Vout. But our device is a simple buck without any I2C/PMBus/... interface, if you need Vout adjustment, you may add more circuits to implement (e.g add a MOS switch to change FB resistor).
