New Industry Products

GaN Systems and onsemi Debut a Totem Pole PFC Evaluation Board

August 17, 2021 by Gary Elinoff

The new evaluation board employs onsemi's NCP1680 controller and GaN Systems’ GS66508B 650V Enhancement Mode GaN Transistor.

The two companies have introduced a 300 watt Bridgeless Totem Pole Power Factor Correction Evaluation Board (BTP-PFC). The unit includes On Semiconductor’s NCP1680, a dedicated critical conduction mode (CrM) bridgeless totem pole PFC controller along with GaN Systems' 650 volt, 30 amp GS66508B GaN transistors.

The New Evaluation Board from ON Semiconductor and GaN Systems. Image courtesy of ON Semiconductor

This evaluation board offers an efficient way for power engineers to explore the benefits of gallium nitride (GaN) power semiconductors. GaN Systems' GS66508B offers zero reverse recovery, very low junction-to-case thermal resistance, high switching speeds, and low losses.

The NCP1680 controller enables efficient operation under light load conditions and features digital voltage loop compensation. Near unity power factors are achievable in all operating modes and close to 99% efficiency is attained.

This complete solution also serves to simplify the overall power supply design process while reducing both costs and BOM.


The Partnership Between GaN Systems and ON Semiconductors

This isn’t the first collaboration between the two companies. We previously covered an evaluation board they cooperatively offered that explored GaN based full-bridge and half-bridge power supplies. That was almost two years ago, and the present design is representative of the next step of state-of-the-art power supply design.

As per Jim Witham, CEO at GaN Systems. “Leaders like ON Semiconductor recognize the importance of GaN and are optimizing controllers and creating complementary tools like the new 300W PFC evaluation board we introduced today. These solutions strengthen the GaN industry ecosystem in the goal to make better performing and more cost-effective power electronics."


GaN Systems' GS66508B

This 650 volt, 30 amp enhancement-mode GaN transistor is driven with a maximum of -10V to +7V gate-to-source voltage, with transients as high as -20V to +10V tolerated. Switching frequencies are 10 MHz and higher, and there are zero reverse recovery losses. This semiconductor features a source sense (SS) pin for optimized gate drive. Complete information is available on the GS66508B datasheet.


  • RDS(ON)s at 25℃ and at 150℃ are typically 50mΩ and 129mΩ, respectively
  • Gate-to-source threshold is 1.7V, typical
  • Drain-to-source leakage currents are typically 2µA and 400µA at 25℃ and 150℃, respectively
  • Input, output and reverse transfer capacitances are typically 242pF, 65pF and 1.5pF, respectively

Physical Considerations

  • Size is 7.0 x 8.4mm
  • Operating temperature range is -55 to +150°C


  • RoHS 3 (6+4) compliant


ON Semiconductors NCP1680 Totem Pole Converter

This device, which is described as “the industry's first dedicated critical conduction mode (CrM) bridgeless totem pole PFC controller”,  is at the heart of the 300 watt BTP-PFC evaluation board. It offers constant on time with valley synchronized frequency foldback. These features enable optimized efficiency across the entire load range.

The NCP1680 features zero current detection for critical conduction mode (CrM) operation. There is also discontinuous current mode (DCM) capability with valley synchronized turn-on, allowing for improved efficiency at light loads.


  • The NCP1680 is available in an SOIC-16 package


Applications for the Evaluation Board

The evaluation board enables designers to more quickly develop advanced totem pole PFC designs applicable to power supply applications in:

  • Telecom
  • Data centers
  • Industrial applications
  • Consumer industries