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TAS5613A

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Sreekanth Anegunda
Posted by
on Apr 18 2012 05:36 AM
Prodigy135 points

HI,

I am using TAS5613A power amplifier to drive audio signal (3.5KHz to 4KHz) in PBTL mode. The Load resistance will be around 9-10Ohm. I have constructed the schematics as given in the datasheet, what i noticed is the Output (out A, B, C, D) doesn't have the filter capacitor.

Does it require a filter capacitor in series with the Load and output, if not why we don't need?

Does the load gets damaged if we are not using a series capacitor?

Regards,

Sreekanth

TAS5613A
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  • Don Dapkus
    Posted by
    on Apr 18 2012 09:27 AM
    Guru101325 points

    Hi, Sreehanth,

    Please review this Design Note which I believe addresses your concerns.

    -d2

    -----

    Don Dapkus

    Audio Applications Engineering Manager

    Dallas, TX USA

    Report Abuse
  • Sreekanth Anegunda
    Posted by
    on Jul 09 2012 05:11 AM
    Prodigy135 points

    Hello Don Dapkus,

    Thanks for your reply on my earlier post.

    We have the output noise issue (Hiss) and the input current is High  in Ideal mode, I have constructed the schematics as in Demo board (OPA 1632+TAS5613A). I am applying 35V to the bridge of Power amplifier. The 35V supply current is around 120mA, But in datasheet its around43mA(12V+Half bridge current) when in Ideal. I have configured the power amplifier to PBTL (BD mode).

    I am giving the input to A and B (C is connected to VREG and D is connected to GND). What we observed is Hiss noise at the output (connected Speaker with 9-10Ohm load). Speaker has a frequency response till 16KHz.

    I connecting the preamplifier input to GND for verification, when both input are grounded  we won't hear any HISS but when any one input is grounded then we will hear the HISS at the output (And when input is open also we hear HISS).

    I have attached the Schematics of preamplifier and Power amplifier schematics.

    2844.Power amplifier.pdf

    2072.Preamplifier.pdf

    Regards,

    Sreekanth

    TAS5613A Output Noise
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  • Don Dapkus
    Posted by
    on Jul 10 2012 07:15 AM
    Guru101325 points

    Hi, Sreekanth,

    We are unable to open the file, "Power Amplifier.pdf" 

    It generates an error on our computers.

    Can you re-generate it and re-post it?

    -d2

    -----

    Don Dapkus

    Audio Applications Engineering Manager

    Dallas, TX USA

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  • Sreekanth Anegunda
    Posted by
    on Jul 10 2012 07:30 AM
    Prodigy135 points

    Hi Don Dapkus,

    Please find Attached power amplifier PDF.

    Regards,

    Sreekanth

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  • Sreekanth Anegunda
    Posted by
    on Jul 10 2012 07:35 AM
    Prodigy135 points

    Hello Don Dapkus,

    Please find attached Power amplifier PDF.

    8585.Power amplifier.pdf

    Regards,

    Sreekanth

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  • Don Dapkus
    Posted by
    on Jul 10 2012 09:26 AM
    Guru101325 points

    Sreehanth,

    Great! Thank you.

    Jade will get back with you shortly on this issue.

    -d2

    -----

    Don Dapkus

    Audio Applications Engineering Manager

    Dallas, TX USA

    Report Abuse
  • Jade Goo
    Posted by
    on Jul 10 2012 16:54 PM
    Prodigy140 points

    Hi, Sreekanth,

    I checked your schematic.
    Also, I want to check your layout, too.
    Could you post your layout?

    Thank you.

    Regards,
    Jade

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  • Sreekanth Anegunda
    Posted by
    on Jul 11 2012 00:17 AM
    Prodigy135 points

    Hi jade,

    How are you jade?

    Hope schematics is fine.

    I cannot post Layout as it is confidential.

    If you can give your mail Id then i can send it to you.

    Regards,

    Sreekanth

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  • Don Dapkus
    Posted by
    on Jul 15 2012 09:28 AM
    Guru101325 points

    Hi, Sreekanth,

    Sorry for the delay. One of the guys is looking at your question.

    -d2

    -----

    Don Dapkus

    Audio Applications Engineering Manager

    Dallas, TX USA

    Report Abuse
  • Sreekanth Anegunda
    Posted by
    on Jul 16 2012 01:40 AM
    Prodigy135 points

    Hello Don Dapkus,

    Mr Jade goo requested for PCB layout and i have sent them already But not received any comments or suggestion from him.

    looking forward for solution.

    Regards,

    Sreekanth

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  • Sreekanth Anegunda
    Posted by
    on Jul 16 2012 01:40 AM
    Prodigy135 points

    Hello All,

    I am using TAS5613A for one of our product, I have constructed the schematics as in Demo board (OPA 1632+TAS5613A). I am applying 35V to the bridge of Power amplifier. The 35V supply current is around 120mA, But in datasheet its around43mA when no input is applied. I have configured the power amplifier to PBTL (BD mode).

    I am giving the input to A and B (C is connected to VREG and D is connected to GND). What we observed is there is Hiss noise at the output (Speaker with 9-10Ohm load).

    I tried connecting the preamplifier input to GND for verification, when both input are grounded the we won't hear any HISS but when any one input is grounded then we will hear the HISS at the output (And when input is open also we hear HISS).

    2844.Power amplifier.pdf

    2072.Preamplifier.pdf

    TAS5613A
    Report Abuse
  • Jade Goo
    Posted by
    on Jul 17 2012 10:36 AM
    Suggested Answer
    Prodigy140 points

    Hi Sreekanth,

    I checked your schematic and layout.

    1. I found Audio Preamplifier(IC401) output connect to blocking capacitor(C313. C319) and connect to INPUT_A, B of TAS5613A.
      Preamplifier output source is voltage and TAS5613A input source is voltage, too.
      In this case, preamplifier output impedance is low impedance and TAS5613A input impedance is high impedance.
      So, blocking capacitor(C313, C319) need to placed near TAS5613A input pin, because of impedance value difference.

      Trace length between the 5613A input pin and the blocking capacitor is susceptible to noise pick-up, and this distance should be minimized.
       
    2. Also, I want to know your board's output integrated noise(Vn), in case of datasheet, Vn was 185uV. 

      Could you measured your board’s output integrated noise and please let me know.

    Thank you.

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  • Sreekanth Anegunda
    Posted by
    on Jul 18 2012 02:12 AM
    Prodigy135 points

    Hi Jade,

    Thank you for your review on our PCB layout.

    I am are using a square heatsink for power amplifier so the DC blocking capacitors are bit far from the input of power amplifier.

    What i observed is when no input is connected to the pre amplifier we wont hear any noise, but if i ground any one input of pre amplifier we start hearing noise at the output.

    i tried grounding both the input of pre amplifier but the result is same.

    i don't know what is the reason for that.

    Looking forward for your earliest reply.

    I will measure the output integrated noise and let you know the same.

    Thanks & regards,

    Sreekanth

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  • Sreekanth Anegunda
    Posted by
    on Jul 23 2012 03:14 AM
    Prodigy135 points

    HI Jade,

    I have not received any update from your side waiting for your reply.

    Regards,

    Sreekanth

    TAS5613A
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  • Don Dapkus
    Posted by
    on Jul 31 2012 08:52 AM
    Guru101325 points

    Sreekanth,

    Could it be that your ground is noisy and injecting noise into the amp?

    Did you get a chance to measure the noise floor? And FFT might be useful, too.

    -d2

    -----

    Don Dapkus

    Audio Applications Engineering Manager

    Dallas, TX USA

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