In addition to the low RDS(ON), the lateral structure of the eGaN FET makes it a very low-charge device. It has the capability of switching hundreds of volts in just a few nanoseconds, enabling multi-megahertz switching. This capability leads to smaller power converters, and higher-fidelity class D audio amplifiers. Most important for switching performance is gate-drain capacitance - CGD. With the lateral device structure, CGD comes only from a small corner of the gate. An extremely low CGD leads to eGaN FET’s ability to switch voltage very rapidly. Capacitance curves for the EPC2001 are shown in this figure. Again, eGaN FETs look similar to silicon except that, for a similar on-resistance, the capacitances are significantly lower and “flatten out” much sooner. Gate-source capacitance, CGS, consists of the junction from the gate to the channel, and the capacitance of the dielectric between the gate and the field plate. CGS is large when compared with CGD, but since CGD flattens out to a non-negligible value quickly, this cumulative gate-drain charge - QGD – change impacts dV/dt immunity with increasing drain-to-source voltage. The 40-V eGaN FETs (EPC2014 and EPC2015) have excellent Miller ratios (QGD/QGS less than 0.8), while the 200-V eGaN FETs (EPC2010 & EPC2012) have Miller ratios greater than 1 and therefore require some careful gate-driver design. Overall, the value of CGS is still small when compared with silicon MOSFETs, enabling very short delay times and excellent controllability in low duty-cycle applications. Drain-source capacitance, CDS, is also small, being limited to the capacitance across the dielectric from the field plate to the drain.