Stats

Locked Locked
Replies 4
Subscribers 63
Views 4547
Members are here 0

This discussion has been locked.

You can no longer post new replies to this discussion. If you have a question you can start a new discussion

passive mixer-first receiver IIP3 simulation: IM3 curve not 3dB/dB

Hi,

I design a common passive mixer-first receiver(passive mixer +TIA) in TSMC65LP CMOS process. In the test bench, I drive the receiver with a port , then a idea_bulun , then an ac coupling capacitor connect to the receiver. I use HB method to simulate the IIP3 of the receiver(Lab 10: IP3 Calculation (hb with Three Tones) ). I have two questions:

1. why the IM3 curve is not 3dB/dB ?

2. when I set different "number of harmonics"（from auto 3 3 to 3 2 2）, the IM3 curve change greatly, but the slope is still non-monotonic.

Why is the difference so significant and how can I simulate the correct curve ?

Thank you!

Andrew Beckett over 5 years ago

I'm not sure reducing the number of harmonics is very likely to help, but there are known challenges with simulating IP3 with passive mixers due to limitations in the bsim4 and bsim3v3 models. See this article: Difficulties simulating IP3 on a switched-FET mixer (which references a paper from IBM describing the problem too). It's related to the fact that the derivatives in the model are not smooth at Vds=0 - but the paper includes more details.

Regards,

Andrew.
Cancel
Vote Up 0 Vote Down

Cancel
Joy wang over 5 years ago in reply to Andrew Beckett

Hi Andrew:

thank you. It seems that I don't have the access to support.cadence.com.
Cancel
Vote Up 0 Vote Down

Cancel
Andrew Beckett over 5 years ago in reply to Joy wang

Here's a link to the IBM paper: https://briefs.techconnect.org/papers/linfet-a-bsim-class-fet-model-with-smooth-derivatives-at-vds0/

Andrew
Cancel
Vote Up 0 Vote Down

Cancel
Joy wang over 5 years ago in reply to Andrew Beckett

Thanks again Andrew!
Cancel
Vote Up 0 Vote Down

Cancel

Community Guidelines

The Cadence Design Communities support Cadence users and technologists interacting to exchange ideas, news, technical information, and best practices to solve problems and get the most from Cadence technology. 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. By accessing, contributing, using or downloading any materials from the site, you agree to be bound by the full Community Guidelines.