All of the stand-alone Rg testers incorporate the FET gate parameter tester board with a relay matrix and a Kelvin test circuit. The Kelvin test is to check the continuity of the force and sense contacts onto the pins of the device under test. Communication with the tester is through a high speed serial link.

The first variant, for larger devices, has an internal calibration circuit and two device outputs which enable it to easily test dual devices within a single package. Several manufacturers now make dual low voltage power MOSFET devices, including complementary pairs, which are available in SO-8 style packages.

The second variant has no internal calibration circuit and can test only a single device. This allowed us to improve the board layout so that the there is minimal extra stray capacitance and inductance in the measurement path. This unit keeps the Kelvin test circuit and can optionally connect the device source and drain together.

The third variant adds a voltage bias circuit and the ability to drive up to eight external relays on the handler interface. This unit keeps the Kelvin test circuit and can connect the device source and drain together. See stand-alone test head 3 for a full description of the capabilities of this unit.