This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Dead Simple Stereo ADC/DAC Recommendation Please

Other Parts Discussed in Thread: PCM5242, PCM5102A, PCM4201, PCM1840, PCM1861, PCM1860

Hello TI Staff and E2E Community,

I'm looking for a stereo (2 channel) I2S to Analog solution, both in and out (ADC to I2S and I2S to DAC), that is:

1. Capable of at least 24-bit, 96kHz

2. Can accept an external Master Clock of 256 fs =  12,288 MHz

3. Has no DSP

4. Dead simple to implement in hardware, i.e needs no EEPROM

5. Pro Audio level of performance regarding DR, THD, etc

I understand that my requirements above may require separate ICs for ADC and DAC, as all of the codecs I've seen require register read/write config via EEPROM or MCU.

If I had my way, in addition to the above:

A) The ADC could accommodate mic or line input levels, as well as single-ended or differential inputs

B) The DAC would provide both single-ended and differential outputs, and maybe even have a stereo headphone output

I know that everything I'm looking for is in the modern codecs, but I just don't have time to learn to configure them via register R/W. Call me super old school and I will own that!

The key here is dead simple to implement, with the highest audio quality possible.

I would grateful for any recommendations you can provide!

Kind regards,

Jeffrey Bruton

  • Hi Jeffrey,

    This could be handled by a codec, but there is something to be said for having a discrete DAC and ADC, for simplicities sake.  If you want them to share a single I2S bus, you will need to implement TDM, which limits the selection.  

    For the DAC, I recommend the PCM5242, which is a differential line output DAC, though you can just use one output if you want it to be single-ended.  While it has a very large feature set, you certainly do not need to use all of the features to get a great sound.  With the correct I2S format input, you do not even need to configure it.

    If you want something simpler, you could use the PCM5102A.

    I'll pass this thread to my ADC colleagues for their input.

    Thanks,

    Paul

  • Hello,

    The PCM1840 and PCM4201 are high-quality hardware controlled ADCs that should work well for this application.  Technically the 1840 is a quad ADC, but it's our latest HW controlled offering. The PCM1860 or PCM1861 would be other stereo options with the PCM1861 being the higher-performing variant.

  • Hi Paul,

    Thanks for the reply and suggestions.

     The converters will be interfacing via I2S with a device that will be providing all the clocking: Master (sometimes referred to as System) Clock at 256 fs; Bit Clock; LRClock; and of course has DIn and DOut.  A couple of questions:

    1. Regarding using a discrete ADC and DAC, you mention that if the converters are going to share an I2S bus then TDM must be implemented. Sorry if this is a very basic question, but can't they just both be given all three clocks from the Master device, and also send/receive their data streams to/from the Master device (ADC and DAC respectively)?

    2. Re: the PCM5242, you mention with the correct I2S format it doesn't even need to be configured. Would the MCLK at 256 fs, LRCLK, and BCLK (and of course the Data Stream) be such an I2S format? I thought I2S was I2S, with only the MCLK possibly being at a different rate (or not provided if the converter is in Master Mode) and that it doesn't have various formats. I'm aware of Left and Right Justified but thought they were different formats and not technically I2S.

    Thanks again and kind regards,

    Jeffrey Bruton

  • Hi Colin,

    Thanks for the suggestions.

    Kind regards,

    Jeffrey Bruton

  • Hi Jeffrey,

    1. If you have the MCU resources to provide a DIN and DOUT (for the ADC and DAC), then you can definitely have separate buses.  I just mentioned it as not all MCUs support it.  Some use TDM (time-division multiplexing) were some of the channels are assigned to the ADC and some to the DACs, and they share one bus.

    2. There are few versions of I2S (standard I2S, right-justified I2S, left-justified I2S), standard I2S is the default on the PCM5242.  The device automatically configures for a subset of clock rates. See table 32 in the PCM5242 datasheet.  Or you can consider the PCM5102A, which just has a few hardware pins to configure it.

    Thanks,

    Paul

  • Hi Paul,

    Thanks for the quick reply and clarification.

    We will just being using standard I2S so that probably gives us a bit more options as it sounds like that is the power up default of some converters/codecs.

    Thanks again and kind regards,

    Jeffrey Bruton