TAC5112: Dynamic range when the ADC is single-ended

Hi,

My apologies for the late response. I will get back to you over the next few days about questions 2-5. But, for your first question, the dynamic range in single-ended mode will be -6dB from the differential mode rating, since the input will only have half of the dynamic range available. So, 105dB ADC differential dynamic range for the TAC5112 will turn to 99dB in single ended mode. For the TAC5142, 103dB will turn to 97dB.

Also, are you using the TAC5112 or the TAC5142? The 5142 is hardware-controlled, while the 5112 is software controlled (I2C). 

I will ask our systems team about the mic bias and power tune mode. As for your question #4, check section 8.3.6.2.1 in the datasheet for some phase plots of the decimation filters. Are these the ones you mean?

Best,
Mir

Hi Mir

Thanks for your reply.
I am waiting for other answers.
I am planning to use TAC5112, but was checking the datasheet as TAC5142 is also a candidate for consideration and had a question.
Also, the values you gave me are different from the datasheet, what is the DR of the DAC as well?
Furthermore, when do you plan to change the datasheet?

Best Regards,
Ryu.

Hi Ryu-san,

So sorry about the inconsistencies in my answer, I saw 105dB on the ti.com rating for the part... I will ask our systems expert about this inconsistency and let you know what the official rating should be when I hear back. Since the device is not fully released, the datasheet may not be finalized. But, let's assume the lower value for now, just to be safe. Then, according to the datasheet, the TAC5112 has a 100dB dynamic range on the ADC in differential mode, so single ended will be 94dB. The dynamic range of the DAC is rated to 106dB, so single-ended would be 100dB. Again, there are inconsistencies with the website, so I will get back to you on the official rating but this is the lowest that is listed. Sorry about this. The datasheet will be changed to the official values when the device is fully tested and ready for release, hopefully in the next few weeks to months but I do not have an exact date. Other parts in the new line of converters have already been released so we hope to release these as soon as possible.

As for the filters being changed while the device is active, I tested it with an EVM, and while the filters screen is greyed out when the device is active, I was able to run I2C commands to change the filter while active and saw the change on the scope. So, you should be able to change the biquad filters (including high pass) while active. I am asking about the decimation filters for you.

I will let you know the answers to your other questions when I hear back, I'll get back to you in the next couple of days. Let me know if you have any more questions.

Best,
Mir

Hi Ryu-san,

I have some exciting updates from our systems team. Firstly, the ti.com dynamic range data is the updated number based on performance - so the values are 105dB on the ADC and 114dB on DAC dynamic range performance for differential - so -6dB from that for the single-ended modes of both. This will be updated in the datasheet soon. 

Power tune mode explanation will be added in the finalized release datasheet, but I was told that "it is a mode in which device consumes less power based on certain performance tradeoffs." Let me know if you need more explanation than this and I can ask more.

Also, for the TAC5142, the mic bias is NOT programmable, but it is always equal to VREF voltage. 

Let me know if you need more follow up with these questions!

Best,
Mir

Hi Mir,

Thanks for your reply.
Please tell me about this additionally.

Mir Jeffres said:

As for your question #4, check section 8.3.6.2.1 in the datasheet for some phase plots of the decimation filters. Are these the ones you mean?

I would like information on group delay and characteristic graphs when low-latency and ultra-latency filters are used instead of decimation filters.

Best Regards,
Ryu.

Hi,

Group delay changes based on the sampling rate, just to make sure what sample rate are you looking at? I can ask our systems team about the specifics, I'm not sure if we have them though. The low-latency filters are a type of decimation filter as well so it may not be any different than what is in the datasheet. I will let you know when I hear back, likely Monday.

Best,
Mir

Hi,

I heard back from the team, they will send me the data for 48k sampling rate tomorrow and I will send it here.

Best,
Mir

Hi Mir,

Thanks for your reply.
Okay, I'll wait.

Best Regards,
Ryu.

Hi,

I did not hear back today but I will send as soon as I get this data. In the meantime, please do not respond here so we can avoid a late response flag, unless you have further questions I can help with!

Thanks,
Mir

Hi Mir,

Thanks for your reply.
I am aware of the contents.
I expect that the waveforms will also be attached to the datasheet.

Best Regards,
Ryu.