The MMBF5457 from onsemi is a Junction Field Effect Transistor (JFET) with Drain Saturation Current 1.0 to 5.0 mA, Gate Source Voltage -25 V, Gate Current 10 mA, Gate Reverse Current -1 to -200 nA, Power Dissipation 0.35 W. Tags: Surface Mount. More details for MMBF5457 can be seen below.