As more and more portable audio devices hit the market such as DVD players, MP3 players and even cell phones with audio features such as FM radio and MP3, board space is getting more and more scarce. Thus solution size for a particular function is very important. Design engineers are trying to find ways to optimize the amount of components needed to complete the desired functions. Driving audio signals into headphones has always been one area where DC-blocking capacitors have been needed, the replacement solution has its limitation, or is simply not practical nor wanted.

This article weighs headphone amplifier architectures, explains their pros and cons, and introduces a novel solution that solves issues created by some headphone amplifier architectures.