I am utilising the LT83203 to convert a 12V input supply to 1.7V output supply.
The capacitor connected to the Vc pin (Cc) is 3.6 pF for my design.
But, due to unavailabiltiy of this capacitor, I'm thinking of using the 3.3 pF or 3.9 pF ones (these two are available).
Which one of these capacitors should I go for so that my output voltage remains relatively the same?
What are the implications of this capacitor in the working of this IC? I do know that this pin is connected to the error amplifier output, but how exactly are we compensating the control loop using this RC Network at pin 'Vc'?
Please do share your valuable insights.
Hello rireoa
As you indicated this is for error amplifier. It arranges the control loop of the buck and giving certain phase margins for the stability.
You can use LTPowerCAD for trying different caps and see how much phase margins at the buck you will have.
A rule of thumb is to have at least 45° phase margin at the cut-off frequency.
https://www.analog.com/en/resources/technical-articles/understanding-power-supply-loop-stability-and-compensation-part-2.html
