ABSTRACT
Table 18.3 shows that the best noise and ripple performance that can be expected from a simple LM317 regulator circuit is about −86 dBu (39 uV rms) and this still contains a substantial ripple component. The reservoir capacitors are already quite large at 4700 uF, so what is to be done if lower ripple levels are needed? The options are:
1. Look for a higher-performance IC regulator. They will cost more and there are likely to be issues with single sourcing.
