The BB639 from Infineon Technologies is a Varactor Diode with Capacitance 38.3 pF (CT1), 29.75 pF(CT2), Capacitance Ratio 14.7 (1/28V), Forward Continous Currenrt 20.0 mA, Peak reverse voltage 30 V, Reverse Voltage 30 V. Tags: Surface Mount. More details for BB639 can be seen below.