A common feature in most of today's electronic devices – including cell phone, PDAs, notebooks, handheld media players, game systems, and so on, is the provision for connecting to external accessories. The devices therefore include dedicated logic circuitry that can detect not only the presence of an accessory, but also the type.

The TAx5x1x includes extensive capability to monitor a headphone, microphone (mic), or headset jack, determine if an audio plug has been inserted, and then detect what type of headset is wired to the plug. This application note mainly discusses the headset detection scheme for two different headset output configurations: pseudo-differential (capacitor-less) output, and ac-coupled output. The content of this document applies to the TAD5212, TAD5112, TAC5212, TAC5112, TAC5211, TAC5111, TAD5212-Q1, TAD5112-Q1, TAC5212-Q1, TAC5112-Q1, and TAC5111-Q1