TS3A227E: Asking for the TS3A227E schematic review especially for the TIP and DET_TRIGGER pins to initiate a detection sequence.

Genius 15605 points

Part Number: TS3A227E

Hi Team,
Could you help review TS3A227E schemtic? especially for the TIP and DET_TRIGGER pin.

codec.pdf

Thanks,
SHH

  • SHH,

    VDD is correctly supplied with 3.3 V which is within the recommended operating conditions.

     

    SCL and SDA look like that are not used and are correctly pulled up to VDD 

     

    MIC_PRESENT is open drain and correctly pulled up to what looks like a 3.3 V

     

    MIC_P correctly connected to microphone

     

    INT# looks like it is not used.  Pin is open drain and correctly shorted to ground  

     

    GNDA for FM support and GND_SENSE for cross talk reduction features not used and grounded 

     

    GND correctly connected to ground

     

    SLEEVE and SLEEVE_SENSE correctly connected to sleeve of audio jack

     

    RING2 and RING2_SENSE correctly connected to ring 2 of audio jack

     

    TIP pin is correctly connected to the tip of the audio jack

     

    DET_TRIGGER is shorted to ground when there is nothing inserted into the audio jack.  When something is inserted the phone jack switch will open and the pull up resistor inside the TS3A227E will take that node to VDD 3.3 V.  This means there will be a low to high transition when a device is inserted into the phone jack. This is incorrect for the TS3A227E which requires a high to low transition on the DET_TRIGGER node to initiate a detection sequence. 

     


    You can use a different phone jack that has a switch like the drawing above.  The connector above has the default state as an open which allows the TS3A227E internal pull-up to keep the node at VDD and then when a headphone is inserted into the phone jack it will close the switch to ground which will pull down that node causing a high to low transition. 

     

    Alternatively you could place a FET in between the DET_TRIGGER pin and have the FET off to allow the DET_TRIGGER pin to be pulled up when nothing is in the phone jack and when something is in the phone jack the FET will turn on and pull the node to ground.   An example of this can be seen in the TS3A227E EVM schematic.


     

    Thank you,

    Adam