Audio Converters

Forum Post: RE: AIC3101 Jack/Headset Detection

Geoff Pickford — Mon, 20 May 2013 01:13:00 GMT

Hello Don,

Thanks for such a fast and useful reply.

Regards,

Geoff

Forum Post: PCM1808 Noise

Ed Green — Sun, 19 May 2013 16:27:00 GMT

Hi TI Forum,

I'm using the PCB1808 (slave mode with 12.288Mhz sclk/Fs=48kHz/I2S 24-bit) and seeing 2 issues:

1) Noise - with no audio input, there is a constant background hiss (I've checked the ampliffier separately and have no issues using another source).

- Have a 47k pull-down on the analog input before the input 10uF electrolytic.

- Using the TPS54331 for 3.3V digital VDD regulation from a 12V power brick (components as per that datasheet's example circuit).

- The 5V analog VCC is being generated from an LM7809 down to 9V then an AMS1117-5.0 to 5V

- Even with the Vin input pin lifted, there is still background noise, though slightly less,but still very audible.

Question: which voltage is the PCM1808 more sensitive to wrt noise (I assumed the 5V analog, but just to confirm). Any other ideas where this noise is coming from?

2) When we play audio, there's a type of screech that occurs at the high frequencies. It sounds like aliasing, but would like someone to confirm. Also, I've not installed the RC anti-aliasing filter after the input 10uF electrolytic (didn't implement the -6db attenuator LPF op-amp circuit in the EVM schematic - chose the direct path but put placeholders for a LPF), but would like some guidance as to appropriate R and C to install (the datasheet gives a LPF of ~ 160kHz, while the EVM has 100KHz for the -6db path, but since the Fs is 48KHz, I'm thinking the LPF should be closer to 30Khz - again, would like someone's confirmation).

Any other suggestions regarding the 2 issues above would also be greatly appreciated.

Thanks for your help,

Forum Post: audio chip

shani wolf — Sun, 19 May 2013 11:20:00 GMT

Hello,

I'm looking for a HW config audio chip with I2S as an input and headphone as output.

Is there somthing u can offer me?

I have found an audio chip with I2S input to line out so a line out to headphone convertor would also be good.

Thanks in advance

shani

Forum Post: RE: TAS3204 radiated noise at 135mhz (clock)

David Alexandrou — Sat, 18 May 2013 23:31:00 GMT

Hello again Susan,

I understand that the person in charge of that hardware has moved on, but we did start using this product before it became NRND, and it is still being sold. It is also the core of our product, I really would have hoped to get some sort of reply in the last two months.

~David

Forum Post: RE: PCM4104 / LPF oscillation

Robert Sorensen — Sat, 18 May 2013 15:52:00 GMT

Hi Don,

Thank you for the inputs.

The circuit has split supply and I assume the load is within tolerance as it is the same as the reference design except somewhat higher gain (higher resistance in the feedback loop). The problem is more likely that the buffer circuit has good common mode voltage performance, but this isn't the case with current and this triggers the problem in my system. I will probably not use the PCM4104 for this application so I will more likely use my preferred current output DAC from IT in stead. I could insert 2 x voltage follower - one for the positive and one for the negative voltage output of PCM4104, but then I will have nearly the same component count as my preferred DAC.

The OPA1632 might do the trick, but then again I am not sure that I have a top performer and I am not sure that I can make the solution shown the first post. Do you know if the Vcom output of the PCM4104 can drive 2 x Vcom inputs of the OPA1632 without buffer?

/Robert

Forum Post: RE: TLV320AIC3204 - ADC "white noise"

J Arbona — Sat, 18 May 2013 15:21:00 GMT

Shlomi,

Schematic and mic look good. Could you ask the customer to put comments on the code for each register to understand what they are trying to do?

Thanks,

J-

Forum Post: RE: How flat is frequency response of AD5102 ?

Debasish Deka — Sat, 18 May 2013 15:18:00 GMT

Thanks Don,

I am referring to the AD51xx family of DACs. I found them to be supporting sampling rates of upto 384k. We were actually looking for some DACs having flat frequency response of up to +/-0.01dB in the range 30Hz to 120kHz.. As I read their datasheets I could not find references to our requirements, but potentially I suppose this family of DACs should satisfy our requirements.

By AD51xx I meant the AD510x series - AD5100,AD5101,AD5102 and the AD512x series namely AD5121 and AD5122.

I suppose their features are similar other than AD510x supporting only hardware control and AD512x supporting both hardware and software control.

I have additional requirements to specify but this is the most important one. So once I can be sure of this we can continue further.

Forum Post: RE: Is there any driver, as for, TLV320AIC1110 carried out Linux correspondence?

Don Dapkus — Sat, 18 May 2013 15:14:00 GMT

Hi, Satoshi,

Sorry for the delay in getting back to you.

I doubt we have anything, but I have asked our driver guy to respond.

-d2

Forum Post: RE: SRC4182 / DC level output at mute mode

S.Satoshi — Sat, 18 May 2013 15:06:00 GMT

Hi Don-san,

We need to explain the cause of this phenomenon to close this question. I prepared the draft with TIJ person, so can you check it and give your comments if it is needed to edit.

SRC4182 has interpolation filter and it buffer the data. The length of the data is set by group delay. If the SDIN and BCKI are lost at the same time, the data is remained in the buffer.
After the BCKI is lost, the data in buffer is not cleared and the remained data is output continuously because the BCKI is not provided and so the data is not updated.
So the data in buffer is cleared and no data is output if the SDIN is zero data at BCKI is lost.
This output of buffered data can be stopped by muting SRC4182.
This is assumed operation, so any damage or quality issue is not concerned.

Best Regards,

Sonoki

Forum Post: RE: AIC3262 and digital microphone connections (4x digital mic)

Don Dapkus — Sat, 18 May 2013 14:59:00 GMT

Hi, Jukka,

Welcome to e2e, and thanks for your interest in our products!

I have asked my colleague to look into your question.

-d2

Forum Post: RE: TLV320AIC3106 PCM and Analog Volume

Don Dapkus — Sat, 18 May 2013 14:56:00 GMT

Hi, Shekhar,

My colleague listed the options you have -- it's up to you to decide which is best for your application and go from there.

-d2

Forum Post: RE: Request for more Basic DSP blocks in PurePath

Don Dapkus — Sat, 18 May 2013 14:21:00 GMT

Hi, Markus,

I have asked my colleague to address your concerns.

-d2

Forum Post: RE: AIC3254 AEC

Don Dapkus — Sat, 18 May 2013 14:14:00 GMT

Hi, Matt,

Getting AEC to work correctly in a system is probably beyond the scope of this forum.

I suggest you check with your local TI sales office or authorized distributor and ask them for assistance.

-d2

Forum Post: RE: Run AIC3254EVM-K without USB

Don Dapkus — Sat, 18 May 2013 14:12:00 GMT

Hi, Matthew,

I suspect the problem is in clocking. When you unplug the USB, I bet the clocks go away. Can you verify that?

-d2

Forum Post: RE: LM49352 - Using the LM49352-I2C-Interface-Software

Don Dapkus — Sat, 18 May 2013 14:02:00 GMT

Hi, Claus,

Unfortunately, that s/w requires the use of an interface board which is now obsolete (that's why there is no EVM listed in the Product Folder). I will have it removed to eliminate future confusion.

My suggest is to get an I2C to USB writer, and write the registers directly. Sorry that we don't have an easier way for you to do this...

-d2

Forum Post: RE: set sampling frequency with AIC3204

Don Dapkus — Sat, 18 May 2013 13:58:00 GMT

Hi, Albert,

I believe the GUI for the EVM includes a PLL calculator which might help you correctly configure the PLL.

http://www.ti.com/litv/zip/sloc128b

-d2

Forum Post: RE: PCM270xC: Enable/Disable control for jack sense functionality

Don Dapkus — Sat, 18 May 2013 13:55:00 GMT

Hi, John,

This was not part of the original design spec for this product, so I unfortunately don't have any info on how to do this. Maybe someone in the community has developed something they are willing to share with you.

-d2

Forum Post: RE: PCM9211 Configuration issue

Jacky Wang(QD) — Sat, 18 May 2013 12:46:00 GMT

Hi Sonu,

Can you provide your schematic and PCB layout for me?

Thanks.

Forum Post: RE: PCM1792A

Glenn Fasnacht — Fri, 17 May 2013 11:01:00 GMT

Yes, I completely understand the concept of a delta sigma and noise shaping. I also know that there would be more appropriate DACs, but for now I'm stuck with this one in the design and have to (somehow) get this to work.

Noise shaping pushes the quantization noise up into higher frequencies where they have no practical effect on the output. My problem is low frequency noise, <20Hz, which, in audio applications, also has no practical effect since listener's ears don't respond to frequencies below 20Hz. Unfortunately, mine is not an audio application and my users do care about low frequency noise.

The noise I'm seeing looks like 1/f noise and is significant! Over a 20 second period it can be as large as -50dBfs (30mV p-p out of 10V). The question I have is, is this normal for this part or am I doing something wrong in my circuit design or PCB layout that is inducing this, and if so, what might it be? If it is normal for this delta sigma, I will need to do a redesign of the circuit. If it is a layout issue I will need to do a PCB change.

My boss is growing impatient so some help with your part would be truly appreciated. I have much measured data that I can share with you that might point to the source of the problem. I would like to set up a GoToMeeting with you to share that data and discuss the problem.

Forum Post: RE: Humongous capacitors for cell phones and other applications

Nakesha hendry — Fri, 17 May 2013 09:20:00 GMT

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