Diode-connected transistor

File:NPN transistor as diode.png

A diode-connected transistor is a method of creating a two-terminal rectifying device (a diode) out of a three-terminal transistor. A characteristic of diode-connected transistors is that they are always in the saturation region for metal–oxide–semiconductor field-effect transistors (MOSFETs) and junction-gate field-effect transistors (JFETs), and in the active region for bipolar junction transistors (BJTs).

A diode-connected transistor is made by connecting

• the base and collector of a BJT
• the drain and source of a JFEThttp://www.ti.com/lit/an/sboa058/sboa058.pdf {{Bare URL PDF|date=March 2022}}
• the gate and drain of a MOSFET

Diode-connected transistors are used in current mirrors to provide a voltage drop that tracks that of the other transistor as temperature changes.{{cite web | url=http://electronics.stackexchange.com/questions/50633/transistor-configured-as-diode | title=Usage of a transistor configured as diode }} They also have very low reverse leakage currents.{{cite web | url=http://electronicscircuit1.blogspot.com/2009/03/common-circuit-applicationjfet-diode.html | title=Electronic Device and Circuit Theory Electronics: Common Circuit Application(JFET Diode) | date=17 March 2009 }}