A Small size broadband lumped element balun is presented. Analytical expressions for the component values are derived from cascade analysis. The design is a development of the out-of-phase power splitter of second order. This balun maintains the same amplitude balance as the out-of-phase power splitter; but has substantially improved phase balance; and a reduced size. With ideal components the phase balance is 0Â°; and the amplitude balance less than +/- 0.2dB over more than one octave bandwidth. An experimental demonstrator fabricated by chip components soldered on 0.8 mm PTFE laminate verifies the performance qualitatively. The size of the demonstrator; designed for 3 GHz; is 6*6 mm2.