The PN4857A from InterFET is a Junction Field Effect Transistor (JFET) with Drain Saturation Current 20 to 100 mA, Gate Source Voltage -40 V, Drain Source Resistance 40 Ohm, Gate Current 50 mA, Gate Reverse Current -500 nA. Tags: Through Hole. More details for PN4857A can be seen below.