Cadence® system design and verification solutions, integrated under our Verification Suite, provide the simulation, acceleration, emulation, and management capabilities.
Verification Suite Related Products A-Z
Cadence® digital design and signoff solutions provide a fast path to design closure and better predictability, helping you meet your power, performance, and area (PPA) targets.
Full-Flow Digital Solution Related Products A-Z
Cadence® custom, analog, and RF design solutions can help you save time by automating many routine tasks, from block-level and mixed-signal simulation to routing and library characterization.
Overview Related Products A-Z
Driving efficiency and accuracy in advanced packaging, system planning, and multi-fabric interoperability, Cadence® package implementation products deliver the automation and accuracy.
Cadence® PCB design solutions enable shorter, more predictable design cycles with greater integration of component design and system-level simulation for a constraint-driven flow.
An open IP platform for you to customize your app-driven SoC design.
Comprehensive solutions and methodologies.
Helping you meet your broader business goals.
A global customer support infrastructure with around-the-clock help.
More Support Log In
24/7 Support - Cadence Online Support
Locate the latest software updates, service request, technical documentation, solutions and more in your personalized environment.
Cadence offers various software services for download. This page describes our offerings, including the Allegro FREE Physical Viewer.
The Cadence Academic Network helps build strong relationships between academia and industry, and promotes the proliferation of leading-edge technologies and methodologies at universities renowned for their engineering and design excellence.
Participate in CDNLive
A huge knowledge exchange platform for academia to network with industry. We are looking for academic speakers to talk about their research to the industry attendees at the Academic Track at CDNLive EMEA and Silicon Valley.
Come & Meet Us @ Events
A huge knowledge exchange platform for academia. We are looking for academic speakers to talk about their research to industry attendees.
Americas University Software Program
Join the 250+ qualified Americas member universities who have already incorporated Cadence EDA software into their classrooms and academic research projects.
EMEA University Software Program
In EMEA, Cadence works with EUROPRACTICE to ensure cost-effective availability of our extensive electronic design automation (EDA) tools for non-commercial activities.
Apply Now For Jobs
If you are a recent college graduate or a student looking for internship. Visit our exclusive job search page for interns and recent college graduate jobs.
Cadence is a Great Place to do great work
Learn more about our internship program and visit our careers page to do meaningful work and make a great impact.
Get the most out of your investment in Cadence technologies through a wide range of training offerings.
Overview All Courses Asia Pacific EMEANorth America
Instructor-led training [ILT] are live classes that are offered in our state-of-the-art classrooms at our worldwide training centers, at your site, or as a Virtual classroom.
Online Training is delivered over the web to let you proceed at your own pace, anytime and anywhere.
Exchange ideas, news, technical information, and best practices.
The community is open to everyone, and to provide the most value, we require participants to follow our Community Guidelines that facilitate a quality exchange of ideas and information.
It's not all about the technology. Here we exchange ideas on the Cadence Academic Network and other subjects of general interest.
Cadence is a leading provider of system design tools, software, IP, and services.
In order to apply a Gaussian distribution to a device parameter for Monte Carlo simulations, I have to use a line of code such as the following in the model file:
vary vthnmis_rf dist=gauss std=1/1
This came right out of a real model file from a TSMC process. Can anyone tell me what the units on std are? vthnmis is a quantity that is added to vt, and it should be in volts. Standard deviation can't be in volts, so I am not sure what it is. I know that I want to set it to 50mV.
The standard deviation is in whatever units the parameter vthnmis_rf is in. You need to look in the model files to see where this parameter is defined (to find the mean), and also where it is used. My guess is that it is a normalized value, and is being scaled in an equation elsewhere in the model file.
In reply to Andrew Beckett:
Thanks Andrew. Your tip was helpful, but I didn't quite figure out how to use that factor to control st dev of vth. The example I pasted in was actually from another part of the model file and wasn't the best example. Below are all the lines from the model file that I think factor in to vth for the n device.
vary par1 dist=gauss std=1/3
// vary par2 dist=gauss std=1/3
// vary par3 dist=gauss std=1/3
// vary par4 dist=gauss std=1/3
// vary par5 dist=gauss std=1/3
vary vthnmis dist=gauss std=1/1
vary dlnmis dist=gauss std=1/1
vary dwnmis dist=gauss std=1/1
vary toxnmis dist=gauss std=1/1
vary vthpmis dist=gauss std=1/1
vary dlpmis dist=gauss std=1/1
vary dwpmis dist=gauss std=1/1
vary toxpmis dist=gauss std=1/1
In the nch_mc section:
parameters fac_n=1.00 * 2.4
dvthn=a1n * fac_n * 0.0095
in the model section:
vth0=0.4365561 + dvthn
I am using regular nch devices, not the nch_mis devices. When I run the Monte Carlo, the mean and standard deviation of the Vth of an NMOS device with ground and body connected to ground and the drain and gate disconnected are 490mV and 17mV. A std of 2/3 results in std of 34mV. I still don't see how std=1/3 leads to 17mV.
Does this make any sense to you?
In reply to sporre:
It doesn't make that much sense to me - but I suspect there's some aspect that's missing, and unless I wade through a real example (sorry, bit pushed for time at the moment), I probably can't help much more. Are you looking at the vth0 model parameter in the results database, or are you measuring vth some other way? And are you doing enough points?
BTW, unless you use the _mis devices you won't get any mismatch variation - this is the way that that foundry does things for some reason.
Thanks for your tips - I figured it out. I was making a couple of mistakes. Your comment led me to look at the model parameter vth0 of a simple unconnected device instead of the operating point Vth.