The 4393DFN from Linear Systems is a Junction Field Effect Transistor (JFET) with Drain Saturation Current 5 mA, Gate Source Voltage 0.7 to 1 V, Forward Transfer Admittance 6 mS, Continous Drain Current 3 mA, Drain Source Breakdown Voltage 0.35 to 0.4 V. Tags: Surface Mount. More details for 4393DFN can be seen below.