Integrated Amplifiers

Inside the RA180 are four identical, custom Class D amplifier modules, each equipped with a pair of IGO60R070D1 CoolGaN enhancement-mode power transistors from Infineon Technologies [top right in inset PCB picture]. The faster switching speed, lower on resistance and excellent thermal stability of these devices gives them a performance advantage over silicon transistors in this analogue PWM circuit.

However, the circuit architecture is otherwise similar to conventional Class D amplifiers where the inductive output filter network imposes some sensitivity to the speaker load on the final amplifier/system frequency response. PM