BackerShu
|
An intuitive way to understand this is after the dominant pole of the regulator, the output branch act as a resistive divider for the supply noise to appear at the output. As the impedance roll off at 20dB/dec, the supply noise sensitivity falls at the same speed.
A major advantage to have replica biased regulator is to have one degree of freedom to control the regulator loop, 3 poles in replica-biased compared to 2 poles in conventional case. In conventional case, it requires very large caps to make the output pole dominant, whereas in replica-based case, the capacitor to make the RC filter node to be dominant is much less.
The following reference gives you much more details:
A. Arakali, S. Member, S. Gondi, A. Abstract, and P. K. Hanumolu, “Low-Power Supply-Regulation Techniques for Ring Oscillators in Phase-Locked Loops Using a Split-Tuned Architecture,” Solid-State Circuits, IEEE J., vol. 44, no. 8, pp. 2169–2181, 2009.
|
Home
Pages: 1
relationship between regulator supply noise sensitivity and RC filter (Read 2183 times)