TAS5624A Frequency Response Using TAS5538/TAS5548/TAS5558 as PWM Modulator

Sadanori Kato

Other Parts Discussed in Thread: TAS5558, TAS5548, TAS5538, TAS5624A, TPA3116D2

Hi,

Could you please give us the measurement data of TAS5624A's frequency response when using TAS5538/TAS5548/TAS5558 as the pwm modulator?
The evaluated conditions which we would like to obtain are shown as below.
Although the frequency range depends on coefficients of LC filter, we would like to confirm whether the high cut-off frequency is over fs/2 of the nyquist frequency.

<Conditions>
PWM Modulator : TAS5538, TAS5548 and TAS5558
Sampling Rate : 96kHz and 192kHz(Native Audio Processing)
Sweep Frequency Range : 20Hz to 100kHz

Best Regards,
Kato

over 11 years ago

0 user5276421 over 11 years ago

TI__Mastermind 37045 points

Hi, Kato-san,

We'll have take this data since it is not a standard audio range. I will get back to you when we have the data likely by next mid week.

reg,

Paul.

0 Sadanori Kato over 11 years ago in reply to user5276421

Guru 36540 points

Hi Paul-san,

Thank you for your cooperation.
We are looking forward to hearing these evaluated result from you.
In addition, could you please inform us of the following information?

1. Supply Voltage for Power Stage
2. PWM Modulation Mode(AD Mode or BD Mode)
3. Input Condition(AP Screen Capture)
4. TAS5538 Register Conditions(Volume Control Setting, BQ, etc.)
5. Load Impedance for BTL
6. Coefficients of LC filter

Best Regards,
Kato

0 Flora Wang over 11 years ago in reply to Sadanori Kato

TI__Intellectual 2710 points

Hi,Kato-san,

Please kindly see the belowing test picture:

100HZ human cna't hear it, so we only test for Audio band with(20-20Khz).

1. Supply Voltage for Power Stage:30V
2. PWM Modulation Mode(AD Mode or BD Mode):AD Mode
3. Input Condition(AP Screen Capture):

4. TAS5538 Register Conditions(Volume Control Setting, BQ, etc.):it doesn't matter wiht volume,BQ.I don't use any BQ.

5. Load Impedance for BTL:4ohms
6. LC filter:7uH+0.68uf

Thanks,

Flora Wang

0 Sadanori Kato over 11 years ago in reply to Flora Wang

Guru 36540 points

Hi Flora-san,

Thank you for your cooperation.
I will confirm your information and will contact you again if I have any questions.

Best Regards,
Kato

0 Sadanori Kato over 11 years ago in reply to Sadanori Kato

Guru 36540 points

Hi Flora-san,

Since our customer have requested the sweep frequency range from 20Hz to 100kHz, could you please obtain it again and tell me the input port which you used?
In addition, could you please confirm that the input audio signal is not attenuated below 20kHz before TAS5624A just in case?

Best Regards,
Kato

0 Flora Wang over 11 years ago in reply to Sadanori Kato

TI__Intellectual 2710 points

Hi, Kato-san,

For TAS5538,I used SDIN1.

Thanks,

Flora Wang

0 Sadanori Kato over 11 years ago in reply to Flora Wang

Guru 36540 points

Hi Flora-san,

Thank you for your reply.
Our customer does not expect to guarantee a flat frequency response above ~40kHz, would like to know whether the frequency response depends on the performance of TAS5624A.
If we can not obtain the performance such as the frequency response which is mentioned on page 9 of TPA3116D2 data sheet using TAS5624A, I believe that it is one solution.

Best Regards,
Kato

0 Sadanori Kato over 11 years ago in reply to Sadanori Kato

Guru 36540 points

Hi Flora-san,

We got the cooperation to your local FAE and have evaluated the frequency response using TAS5558 and TAS5624A in your local office.
This result is shown as below, however it is a result only for 96kHz.

Best Regards,
Kato

0 Flora Wang over 11 years ago in reply to Sadanori Kato

TI__Intellectual 2710 points

Hi,Kato,

You are right. I get the same result as you.

See the cut off happens nearly 40Khz. Alough it's 192khz,the Processing is actually done at 96kHz,then it's limited by 1/2 fs to avoid any alias of the input signal.

Thanks,

Flora Wang

0 Sadanori Kato over 11 years ago in reply to Flora Wang

Guru 36540 points

Hi Flora-san,

Thank you for your reply.
I will discuss my questions with you in the following post.

http://e2e.ti.com/support/amplifiers/audio_amplifiers/f/6/p/347745/1234383.aspx#1234383

Best Regards,
Kato

0 Sadanori Kato over 11 years ago in reply to Sadanori Kato

Guru 36540 points

Hi Flora-san,

Could you please tell us just in case whether TAS5538 was mounted on the board which you evaluated regarding the frequency response?

Best Regards,
Kato

0 Flora Wang over 11 years ago in reply to Sadanori Kato

TI__Intellectual 2710 points

Hi,Kato,

I used TAS5538. I remember I tested TAS5558 very quick ,the frequency response is the same.

But all the curve I showed to you is tested on TAS5538.

Thanks,

Flora Wang

0 Sadanori Kato over 11 years ago in reply to Flora Wang

Guru 36540 points

Hi Flora-san,

Thank you for explaining so politely.
I understood.

Best Regards,
Kato

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TAS5624A Frequency Response Using TAS5538/TAS5548/TAS5558 as PWM Modulator