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October 24th, 2016

Modular Devices Inc.'s Presents Series *3678 Hybrid EMI Filter

MDI's model *3678 is a compact standalone, low attenuation solution that permits users to meet newer MIL-STD-461D,E,F,G CE102 limits with legacy converters having built-in 461C CE03 filters.

Here are its features/benefits:

  • Compact standalone hybrid solution enables CE03 converters to meet CE102 requirements without retrofit
  • Low attenuation, multi-stage filters minimize risk of converter instability and Middlebrook effects
  • Easily incorporated into new or existing system design layouts as an “add-on” module
  • Choice of package styles, all rugged full hermetic hybrid construction
  • Several grade and screening levels available to suit any reliability requirement
  • Available in all popular bus voltages


MDI model *3678 Hybrid EMI Filters upgrade legacy converters with internal MIL- STD-461C CE03 EMI filters to meet the latest MIL-STD-461D,E,F,G test method requirements.

MDI introduced the hybrid DC-DC converters featuring built-in MIL-STD-461C CE03 EMI filters. 461C CE03 is a recognized EMI specification in widespread use that uses feed-through capacitors and a current probe to measure conducted emissions on power lines in dBμA units.

More recent test methods of MIL-STD-461D,E,F, G CE102 measure conducted emissions in voltage mode using a line impedance stabilization network referenced to a 50 ohm impedance in dBμV units. Also, after adjusting for a 34dB measurement differential, CE102 uses a newer slope-adjusted limit curve as compared to CE03. In the frequency range of 100-400kHz, where many hybrid DC-DC converters operate, the newer CE102 limits can be up to 24dB lower than corresponding CE03 limits. 

The *3678 family of filters, sized to accommodate a broad range of popular satellite, ISS/Orion, airframe and vehcle input voltage buses, incorporate a common mode stage and two low attenuation, low resonance differential mode stages. The resulting design achieves the necessary attenuation for CE102 compliance while minimizing the possibility of excessive input filter impedance mismatch that might otherwise result in DC-DC converter loop instability.

A single filter can serve several DC-DC converters up to the rated maximums and two or more *3678 filters may be used in parallel to serve multiple DC-DC converters sharing the same input bus. More examples can be seen here.