TOP257 YN control pin capacitor
Posted by: kemred
on
In design notes it is written that for 47uF capacitor connected to control pin, we must not use low esr capacitor. Is there any reason for that?
Best regards,
Comments
It is written in AN16, page 10, step 32
Yes its correct.
As I mentioned, we don't advocate use of low esr capacitor for this component. The ESR of the cap contributes toward a zero in the control loop and a low ESR would result in this zero occurring a little later in the spectrum.
If you want to use a low ESR cap I suggest that instead of using a 6.8 ohm external resistor use a 8.2 ohm resistor instead.
Would you let me know which design note says that?
Typically we don't advocate the use of a low ESR capacitor. Infact we ask that designers add an external series resistor (typically 6.8 ohm) for better loop stability...