Single-Ended, 2-Channel GaN Class D Amplifier – Evaluation Board

Single-Ended, 2-Channel GaN Class D Amplifier – Evaluation Board


The EVAL_AUDAMP24 e-mode GaN HEMT-based evaluation board from Infineon Technologies is a 2-channel, 225W/ch (4Ω at ±43V) or 250 W/ch (8Ω at ±63V) half-bridge class D audio power amplifier for high-end Hi-Fi audio systems. This evaluation board demonstrates how to use the IGT40R070D1 E8220 CoolGaN™ gallium nitride transistor together with the MERUS™ IRS20957SPBF controller IC, implement protection circuits, and design an optimum PCB layout.

Potential applications include Hi-Fi amplifiers, AV receivers, Home theater systems, Powered speakers, Musical instrument amplifiers, and other premium audio designs.

The reference design provides all the required housekeeping power supplies for ease of use. The 2-channel design is scalable for power and the number of channels.

The EVAL_AUDAMP24 features a two-channels self-oscillating type pwm modulator for the lowest component count, highest performance and robust design. This topology represents an analog version of a second-order sigma-delta modulation, having a class D switching stage inside the loop.

The benefit of the sigma-delta modulation, in comparison to the carrier-signal based modulation, is that all the error in the audible frequency range is shifted to the inaudible upper-frequency range by nature of its operation. Also, sigma-delta modulation enables the designer to apply sufficient error correction.

Summary of Features

  • Output power:
    • 225W x 2 channels (1% THD+N, 4Ω at ±43V)
    • 250W x 2 channels (1% THD+N, 8Ω at ±63V)
  • Multiple protection features:
    • Overcurrent protection (OCP), high- and low-side e-mode GaN transistors
    • Overvoltage protection (OVP)
    • Undervoltage protection (UVP), high- and low-side e-mode GaN transistors
    • Overtemperature protection (OTP)
  • PWM modulator:
    • Self-oscillating half-bridge topology with optional clock synchronization


  • Clean switching performance
  • Narrow deadtime for better THD
  • Easy to use: compatible with the MERUS™ IRS20957SPBF class D controller
  • Outstanding audio quality
  • High reliability

more information: Infineon Technologies AG

Mike is the founder and editor of, an electronics engineering community/news and project sharing platform. He studied Electronics and Physics and enjoys everything that has moving electrons and fun. His interests lying on solar cells, microcontrollers and switchmode power supplies. Feel free to reach him for feedback, random tips or just to say hello :-)

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