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TS3A225E: Do you have floor noise information?

Part Number: TS3A225E
Other Parts Discussed in Thread: TS3A227E,

I have 3 questions;

1. Specification

In description of table 2 OMTP,  is pin configration wrong?

I think  sleeve pin is ground.

2. headphone information for noise

Do you have information that some headphone has noise(floor noise)?

(Is there any information that causes noise for wrong detection regardless of whether or not the insertion is slow?)

3. How to calculate resistor for noise reduction

According to specifiaction, delay time can adjust to change resistor at DET_TRIGER line.

Please inform how to calculate resistor.

specification only said please adjust it from real data. please inform formula.

Our customer said that some headphone has noise(it has like floor noise).

I investigate root cause, then I confirmed wrong detestion by slow plug-in by our DUT.

I'd like to know do you have similar issue( regardless of  whether or not the insertion is slow)  and countermeasure.

  • User3619629, 

    1) I found this image on the newer TS3A227E devices that shows OMTP and standard headset jack pin assignments with correct pin out. The TS3A227E device will find the correct path based of the impedance between tip and ring2/sleeve.

    2) The THD value specified in the datasheet is acutally THD+N which includes the noise floor.  This an audio device so it is designed to have good THD+N performance.  

    You can see more detail in the new TS3A227E device.  

    I don't understand your question.  Are you hearing noise when the TS3A227E connects the sleeve and ring 2 pins to different locations?  Do you have scope shots or more detailed description of what you are observing? 

    Are you observing noise when there is no power to the TS3A225E?  If there is no ground connection the wires can become antenna.  The new TS3A227E device has depletion FETs which ground the audio lines when VDD = 0V eliminating this phenomenon. 

    3) To adjust the DET_TRIGGER timing is a matter of an RC circuit slowing down the voltage change on the node connecting to DET_TRIGGER pin.  Slowing down this change in voltage keeps the voltage level below the Vih logic threshold longer.  Here is a link to an RC delay calculator I found searching the web.  

    Thank you,

    Adam

  • Dear Adam san,

    Thank you for your reply.

    1) I understand. It is closed.

    2) Unfortunately, I don't know actual phenomenon now. We heard from OEM customer that our product has floor noise by inserting some headphone.

    So I doubt wrong detection that user inserts OMTP headphone but IC detects standard.

    I already know that slow plug-in occurs wrong detection.

    I'd like to confirm whether do you have information that some headphone always occurs wrong detection. 

    3) I understand it doesn't have special formula. It is closed.

  • User3619629,

    2) The only thing I know about always detecting wrong headset using a high impedance headset.  This can rail out the ADC and not make an appropriate detection.  You can see this post for more information.

    Thank you,

    Adam

  • Dear Adam san,

    I received additional information.

    We got a headphone with floor noise. And we checked floor noise using our unit. It has audible

    (other headphone has no floor noise).

    Do you know any reason that some headphone has floor noise except high impedance?

    Please see following comment for our investigation detail:

    We checked headphone impedance, but it has no problem and headpnoe is standard;

    • Tip (Left) to Ring2 : 34Ohm
    • Ring1 (Right) to Ring2: 34Ohm
    • Tip (Left) to Sleeve : 1.97kOhm
    • Ring1 (Right) to Sleeve : 1.97kOhm
    • Ring2 to Sleeve: 1.94kOhm

    We think headphone polarity detaction is correct.

    Then we measured  <1Ohm impedance between Sleeve (pin2) and GND, while between Ring (pin1) and GND the impedance is >MOhm when we inserted it.

    In addiction we measured a voltage of 1.715V between Ring and GND, it means that the MIC_BIAS is connected to the microphone.

    We repeated the test with other headphone (33Ohm, CTIA) and we measured similar values on Sleeve and Ring pins, but the level of the floor noise was much more lower (almost absent).

  • User3619629,

    Based on your impedance measurements with  <1Ohm impedance between Sleeve (pin2) and GND tells me this is a 3-pole headset that doesn't have a microphone.  Since this is a 3-pole headset I would not expect the MIC bias to show up on ring2 and since it is low impedance to ground I would not expect a high voltage measured.

    I'm still not sure what you are describing as noise floor but I'm interpreting it as a low magnitude constant sound heard through the headset speaker.  There are no known issue what you are describing other than what was mentioned above. 

    I would start investigating the differences between the headsets with audible sound and no audible sound. Are there any other differences you can think of?

    Thank you,

    Adam

  • Dear Adam san,

    > Based on your impedance measurements with  <1Ohm impedance between Sleeve (pin2) and GND tells me this is a 3-pole headset that doesn't have a microphone. 

    No, it is 4-pole headset. I think you can confirm if you have headset with similar impedance. please confirm following impedance and voltage.

    In headset impedance is below;

    • Tip (Left) to Ring2 : 34Ohm
    • Ring1 (Right) to Ring2: 34Ohm
    • Tip (Left) to Sleeve : 1.97kOhm
    • Ring1 (Right) to Sleeve : 1.97kOhm
    • Ring2 to Sleeve: 1.94kOhm

    And headset is inserted to our product, then we measured impedance of 3.5mm jack's terminal with power-on,

    • Sleeve to GND(our product GND) : <1Ohm and 1.715V
    • Ring2 to GND(our product GND): > MOhm

    > I'm still not sure what you are describing as noise floor but I'm interpreting it as a low magnitude constant sound heard through the headset speaker. 

    I think your interpretation is correct.

    > I would start investigating the differences between the headsets with audible sound and no audible sound. Are there any other differences you can think of?

    We don't know now. Other headset can't hear noise.

    I got information of headset. It may be 39H00037-01M made by HTC.

    Can you get it and confirm floor noise?