Hi Sundareswaran,

perhaps

- oscillators

and, if not completely covered in the framework of power electronics and data converters,

- analogous filters (passive, active) and digital filters (FIR and IIR).

Focussing more on the analog domain (considering the digital domain as the "easier" one):

* Linear amplifiers

* Limiters

* Precision rectifiers

* High-speed amplifiers

The more you dive into the analog domain, the more additional topics you might discover...

Adding to the respected colleagues, one of the very rich topic is the phase locked loops and delay locked and their applications in communication and instrumentation. The frequency synthesizer is one of the very interesting mixed design challenge.

Best wishes

Good mathematics and physics - that's the basis everywhere.

I would like to stress the point of view of Dr. Dreher that the ability to design amplifiers is the core of analog circuits and their applications. So, the basic amplifiers and their basic buildings blocks such as the differential amplifiers and the active loads and current sources which are classified as basic building blocks of analog circuits. One has to master them to be a good designer. On the top of then is the operational amplifiers. Analog designers must be able to design operational amplifiers for a given specifications. Amixed designer must be able to add to them the basic building blokes of the digital circuits namely the basic logic gate and memory circuits of sram and dram. He must be aware of the decoupling methods between the analog and digital blocks. So, people make research how to isolate the both blocks especially the effect of digital circuit interference on the analog circuits.

So, this answer sums up the answer of Dr. Dreher and the answer of Dr. Poncochar.

Best wishes

Thanks very much for all the answers :)

Main skill for sure is to master using Cadence and layout techniques. Also, how to design different building blocks like current mirrors and amplifiers.... etc.

In terms of digital circuits, it is important to learn how to design your basic cells such as delays, buffers, AND gates, OR gates and flip-flops for low and high frequency applications.