The Designer's Guide Community Forum

The Designer's Guide Community Forum
https://designers-guide.org/forum/YaBB.pl
Simulators >> Circuit Simulators >> Noise analysis of Inverter and Sense amplifier
https://designers-guide.org/forum/YaBB.pl?num=1436371156

Message started by ValarMorghulis on Jul 8^th, 2015, 8:59am

Title: Noise analysis of Inverter and Sense amplifier
Post by ValarMorghulis on Jul 8^th, 2015, 8:59am

I am trying to do the thorough noise analysis of a simple inverter and a sense amplifier using Spectre. What type of input combination and signal should I provide for correct analysis? And what type of output load should I use?

Thank you for your time!

Title: Re: Noise analysis of Inverter and Sense amplifier
Post by Ken Kundert on Jul 8^th, 2015, 9:52am

That all depends on what the inverter will be driving. Many loads are not actually sensitive to noise much of the time. The noise analysis you do should reflect that. If it is driving another gate, then you should probably run some kind of jitter analysis because the gate is only sensitive to noise at threshold crossings and the most natural metric is as a variation in time.

As far as how to load the circuit you are measuring, you should add a load that models the stage that you will be driving.

-Ken

Title: Re: Noise analysis of Inverter and Sense amplifier
Post by ValarMorghulis on Jul 8^th, 2015, 10:08am

Thank you for your reply. Currently I am using 4 cascaded inverters with a 2fF load at the end and I am doing the same for sense amplifier (cascaded). My intention is to analyze the noise considering my circuits will be used to build a large logic family.

And also I am using very small supply voltage (which is almost close to threshold voltage of the transistors) to see noise effects at reduced supply voltage.

In my case, a smaller noise voltage(close to threshold crossing) might impact my circuit behaviour. For sense amplifier, I am interested to use double-ended outputs to drive following stages.

Should I still do the jitter analysis and what should I do for sense amplifier?

Thank you for your time.