The QPI-1, an active electromagnetic-interference (EMI) filter for 48-V dc-dc converter applications, provides over 40 dB of common-mode noise attenuation and over 80 dB of differential-mode attenuation. Active filtering eliminates ringing on converter inputs in response to load and line transients. The filter can be placed in series for higher attenuation or paralleled for higher currents. The QPI-1 costs $19.50 each in quantities of 1000 units. Delivery is from stock to six weeks.