The Barth Model 45003WP Dual Wafer Probe accessory has been specially designed to provide the sameaccuracy as when testing packaged devices in a socket. Testing the TLP characteristics of the device onwafer and later when it is packaged, can provide significantly more information than is available with pass orfail testing with human body model or machine model. Either manner of connecting to the DUT allows veryrepeatable measurements at high pulse currents.To minimize the mechanical problems of crossed needles in connecting to the pads to be tested, a speciallydesigned constant impedance-reversing switch allows easy selection of the TLP pulse polarity at the pads. Auser selectable magnetic or vacuum base allows this TLP probe to be easily moved while maintaining asecure position on the table.Controlled 50 ohm impedance throughout the complete measurement chain of our test system minimizes themeasurement errors associated with the usual 500 ohm resistor connections for ordinary TLP testers.Making measurements at 50 ohm impedance minimizes the effects of parasitics.Just as the Barth TLP Test System connections to the packaged device sockets are constructed with acontrolled 50 ohm impedance, the Barth Model 45003 Dual Wafer Probe accessory also has a controlled 50ohm impedance throughout its connections to the two needle contacts at any two pads.Testing the DUT directly from an inherently low 50 ohm source impedance provides inherently higher pulsecurrents from a clean test pulse with no ringing or overshoot. A perfect sub nanosecond risetime pulsegenerator combined with low distortion measurement probes and controlled impedance connection allowsthe Barth Model 4003 TLP+ Pulse Curve Tracer test system to gather accurate TLP data either on waferor packages.