This reference design is for autonomous audio headset switch applications. Some audio headsets have integrated analog microphones. The GND and MIC connections on the audio jack connector may be swapped depending on the manufacturer. This design has the ability to detect the presence of an analog microphone on the audio headset, detect the pin configuration of the MIC and Ground pins, and switch the system MIC pin to the correct audio jack connector. This allows the customer’s audio solution to work seamlessly with headsets from all manufacturers.

The TS3A226AE is an audio headset switch that detects 3- or 4-pole 3.5mm accessories. For a 4-pole accessory with a microphone, the TS3A226AE also detects the MIC location and routes the microphone and ground signals automatically. The ground signal
is routed through a pair of low-impedance ground FETs (60mΩ typical), resulting minimal impact on audio cross-talk performance. The autonomous detection feature allows end users to plug in accessories with different audio pole configurations into the mobile device and have them operate properly with no added software control and complexity.

Features

• • VDD range = 2.6V to 4.7V with Ground FET switches (60mΩ typ RON)
  • Detection initiated by external trigger pin
  • Supports FM signal transmission through the ground FETs
  • Reduction of click/pop noise
  • THD (Mic): 0.002% Typical
  • 8-kV Contact Discharge (IEC 61000-4-2) ESD rating for Sleeve, Ring2 and Tip

This reference design has been tested by TI. The company has also provided additional resources. You can find additional data about the reference design on the company’s website. To read more about this specific reference design click here.