zrffxx
Newbie level 3
hello,everyone.
I got a problem.
As in the picture,there is a regulator in the red block which is used to generate 1.8V voltage for the other circuits' power supply.When it is alone,it works well and has 30mA driving ability.But when the vco or any oscillator is attached as shown in the picture,the output of regulator has ripples when the oscillator is oscillating.
Why?The vco's frequency is up to 100Mhz. I guess that the voltage of oscillator's output swithed too fast that the output of the regulator cannot follow it.Am I right?So I should increase the opamp's GBW in the regulator?What factor decide the GBW?Equal to the oscillator's maximum frequency?How could I solve this problem?
Thank you very much!
I got a problem.
As in the picture,there is a regulator in the red block which is used to generate 1.8V voltage for the other circuits' power supply.When it is alone,it works well and has 30mA driving ability.But when the vco or any oscillator is attached as shown in the picture,the output of regulator has ripples when the oscillator is oscillating.
Why?The vco's frequency is up to 100Mhz. I guess that the voltage of oscillator's output swithed too fast that the output of the regulator cannot follow it.Am I right?So I should increase the opamp's GBW in the regulator?What factor decide the GBW?Equal to the oscillator's maximum frequency?How could I solve this problem?
Thank you very much!