Three limit sets
CISPR 32 (multimedia equipment), FCC Part 15.107 and CISPR 25 (automotive), with the matching LISN.
Conducted EMI, before the test house.
Your converter, a LISN and the limit line. See the spectrum, the margin and a first filter before you book a lab day.
What does the Conducted-EMI Predictor do?
The Conducted-EMI Predictor takes a switching converter, from a schematic, a template or an imported LTspice .asc file, and computes the conducted-emission spectrum it produces in a line impedance stabilisation network (LISN). It compares the spectrum with CISPR 32, FCC Part 15.107 or CISPR 25 limits using peak, quasi-peak and average detectors, splits differential-mode from common-mode noise, reports the margin, and proposes a first EMI filter. It is a pre-compliance tool: it helps you arrive at the test house with a design that should pass, not a certificate.
Features
Peak, QP and average
The three detectors the standards use, computed from the steady-state spectrum.
DM / CM split
Differential-mode and common-mode noise separated, so you know which filter stage to change.
Filter suggestion
A first filter sized to the margin you need, re-solved with the filter in place.
Limits
Results are predictions for the stated model. Switching edges and board parasitics are estimates; agreement with a test house is not guaranteed and nothing here is a certification.
Every module ships with reference cases that run in our CI. See validation for how results are checked.
Related modules
Circuits & Power Electronics
Browser circuit simulator for power electronics: DC, AC, transient, Bode and exact switching steady state in one solve. Opens LTspice .asc schematics. Runs on Mac, Linux, Windows and Chromebooks.
High-frequency, EMC & Exposure
Wire-antenna and radiated-emission modelling against CISPR 32 limits, and RF field exposure against ICNIRP guidelines, in the browser.
Datasheet Device Models
Fit GaN and SiC FET models from datasheet curves, run a virtual double-pulse test, and get Eon/Eoff switching-loss tables with uncertainty bands.
Try the Conducted-EMI Predictor.
Frequently asked questions
Can simulation replace an EMC test lab?
No. The predictor is for pre-compliance: it finds the problem frequencies and sizes a filter early. Formal compliance still needs an accredited lab.
Which standards does it cover?
CISPR 32 and FCC Part 15.107 for conducted emissions on mains-powered equipment, and CISPR 25 for automotive components.
Can I import my LTspice converter?
Yes. The predictor opens LTspice .asc schematics directly.