Dear Prahlad,

here are some points:

- At SV1 a 100nF cap should be connected from Pin2 to ground.

- Probably you can omit B3, B4 and C27.

- But you need an additional ferrite bead in series to R21! (Most important ferrite bead in your application!)

- Is there a 100nF cap in parallel to C28 at micro? Should so.

- Pi-filter behind IC1 and IC3 are not needed. Use 22R + 10µF/tantal instead.

- But pi-filters are needed arround ICL7660! Add a ferrite bead an some ohmic resistance between C13 and C13 and exchange C1 by a suited Pi-filter.

- AVCC must be derived from VCC, as shown in the datasheet (page 240, figure 109), because AVCC and VCC must never differ by more than +-0.3V! Protection diodes D3 and D7 must be connected to AVCC then.

- For the same reason the circuit arround AVREF needs a change. I would connect AVREF directly to AVCC. To get information about actual value of AVREF you could connect a LM336-2.5V, biased by AVCC, to a free analog input of micro.

Kai