Page 64 - PEN eBook July 2023

Test & Measurement

Figure 4: Example waveform of R DS(on) measurements

small GaN FETs are critical. A customized board for this device was developed to determine if
Keysight’s solderless contact technology would provide repeatable results for this challenging

device (see Figure 3).

After a couple of design iterations to the device holder, including spring tension on the top plate
and alignment holes for the baseplate part registration, we were successful in testing multiple sets
of parts with this design.

To further minimize loop areas for the gate loop and power loop, a multi-layer PCB was leveraged,
enabling trace routing within different layers to minimize the loop areas. The gate drivers and
replaceable R daughter boards were placed on the back side of the PCB, further reducing loop areas.
g

Finally, a simplification of Keysight’s patent-pending current-sensor technology allowed the shunt
to be placed closer to the DUT, reducing power-loop area while further minimizing the insertion
inductance of the sensor. Together, these modifications to Keysight’s existing customized GaN
solution enabled industry-leading results for devices like the EPC2045A.

CONDUCTION-LOSS RESULTS

The test system setup to measure dynamic R is shown in the next table (left). To measure
DS(on)
the repeatability of the system, 10 tests were performed using the same EPC2045A GaN FET,
reseating the device in between each test. The second table (right) shows the results. A max./min.
measurement variation of less than 10 mΩ is very good for a solderless DUT connection technology.
Keysight has ideas for further improvement of this critical parameter.

64 JULY 2023 | www.powerelectronicsnews.com