I have taped out my digital design with efabless. Want to start analog design. I want to work on simple things like ADC, DAC, opamp and various cmos sensors. Where do I start from? I have fairly good idea about circuit design in spice. Is there a flow like open lane which can take spice circuit and create GDS? Link to document and videos will be helpful for me. Thanks.

There are only a few software projects under development that can do the job of analog layout; see, for example #bag (based on the Berkeley Analog Generator) and #fasoc (Mehdi's project at U. Michigan). Most people still do layout by hand for analog.

Can you please share any link about how to create an analog layout by hand? How to simulate that and how to get gds for that

Google "youtube efabless" or go to https://www.youtube.com/channel/UCQdKzzTOgO0S1wc3X0Z1Qkg There are two videos there "Analog Design with Stefan Schippers and Xschem" and "Op-Amp Analog Layout". There are additional videos by Brad Minch (Olin College of Engineering) on using Magic for analog layout. I'm not sure what's out there for klayout tutorials; maybe somebody else can chime in.

Align is a sort of “automatic” Spice to GDS converter, but in its current state I wouldn’t recommend it to a newbie. https://github.com/ALIGN-analoglayout/ALIGN-public

Thanks, @Michael Strothjohann! I should definitely have remembered ALIGN. I knew there was one major one I was missing.

@Michael Strothjohann @Tim Edwards I made a video on using ALIGN and OpenFasoc last year.