Comparison between Analaog and digital layout

[ryusgnal]

What is the different between analog and digital layout? why is analog layout is more complicated?

Thank you.

 

[Alan_Nesta]

Comparation between Analaog and digital layout

I think digital layout can use apr, only timing, power and area need take care; but analog layout should take care to current, matching, noise, ESD and parasitics.
So an analog layout engineer need more experience.

 

[batistuta]

agree with ALAN_NESTA....

 

[stuck_adc]

in digital circuits, there are only two levels - high and low. moreover the transistors work in linear region.

while in analog circuits there are no defined logic levels........signal can take any value.
Even the transistors work in saturation region.
Moreover the analog signals are more prone to noise because of there low voltage swing..........generally we have adc's with input range around 500mv.
this low swing can be easily effected by the substrate noise, i.e. transistor's noise itself.

thus we need to take a lot of care for the analog signals, like matching, shielding, etc.


there are much more issues which you can find in books.....
hope this gives you a basic idea............

 

[manish12]

digital layout has benefit of cell library or cell based design approach.
where as analog don't.

 

[fixrouter4400]

analog layout is more on the design and circuit functionality it's less devices uses not minimum rule to meet requirements.

digital layout has more devices,uses minimum rule etc.

 

[psmon]

Analog cares about matching, digital doesn't.

 

[kpsai26779]

strictly speaking..............there is no difference between analog layout and digital layout.

But the thing is that digital layout can be designed with less specifications (rules) and analog layout with more.

Even if you want to design layout for high speed, high performance digital circuit then you have to follow analog rules.