Product Overview Mini-Circuits’ ADT3-1T-75+ is a 75 DC isolated surface-mount transformer with a secondary/primary im- pedance ratio of 3:1 and a center tap on the secondary winding. This model covers the 1 to 500 MHz band with low insertion loss (1.2 dB), excellent return loss (25 dB within the 1 dB bandwidth, low phase unbal- ance (1˚) and low amplitude unbalance (0.2 dB). The unit comes enclosed in a miniature, 6-lead plastic package measuring just 0.27 x 0.31 x 0.22″, ideal for dense circuit board layouts.