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TS3A227E: Solution to Solve TS3A227E Slow Plug-In Issue

Wayne Chen (ex FAE)
Guru 15950 points
Part Number: TS3A227E

Hi Sirs,

As the datasheet and EVM application mentioned that there is a potential issue that the TS3A227E can finish the detection phase before headset be plugged properly. Would you pls advise if we can add a RC delay circuit between Q1 and DET_TRIGGER# pin to delay its detection phase for >150ms to eliminate slow plug-in issue when I2C is not used? If yes, may we know product line's suggested RC values?
 

Thank you and Best regards,

Wayne Chen
03/03/2018

  • 0
    TI__Mastermind 45350 points

    Wayne,

    The datasheet recommends using an audio jack that has the mechanical switch at the tip pin like you have showed above so that the detection doesn't being until the jack reaches the tip pin.

    You could add an RC delay on the DET_TRIGGER or on the audio jack switch to slow down the pull down effect of the Q1 transistor. 

    Your design calculation for the detection timing will include time it takes for the Vdd and R2 to pull-up the Q1 FET gate and the time it takes the Q1 FET to pull down the DET_TRIGGER pin through the internal 1M ohm pull up resistor to a level below the Vil max voltage.

    This application note also has more information on calculating the RC time constant and sizing the pull up resistors for your desired needs.

    Thank you,

    Adam

       

  • 0 in reply to Adam Torma
    Guru 15950 points
    Thanks for your concern. We are able to fix this issue by RC delay circuit. I will send schematic to you by Email...Wayne Chen