320AIC3106 and POTS phone lines/telephone handset

cobsonchael

So i am hoping this is a simple couple of questions:

can we connect the ADC/DAC to a DAA phone line interface circuit without any components in between? the DAA circuit we are using is CPC5622A. it looks like it has a high impedance for inputs/outputs (600Ohm) and i was wondering if the codec can handle that on any of it's particular inputs/outputs.

in addition we will be using a 150Ohm speaker for a handset and we want it to be able to get LOUD. is the HP Out path too much and we should use a line out or is HP out a better match for this kind of speaker?

thanks

over 8 years ago

0 Luis Fernando Rodriguez S. over 8 years ago

TI__Guru* 84915 points

Hi,

All our audio devices must have an AC-coupling capacitor in the inputs and outputs. This is to ensure that the common-mode voltage will be reached and that there won't be any voltage that could be out of the specs.

Regarding the 150 Ohm speaker, I would suggest the HP output because the line output requires a 10kohm as min. load resistance.

Please let me know if you have more questions or comments.

Best regards,
Luis Fernando Rodríguez S.

0 cobsonchael over 8 years ago in reply to Luis Fernando Rodriguez S.

Mastermind 7930 points

i guess for my first question, put another way:

Will the high impedance of the phone line circuit cause an issue with the codec?

0 Luis Fernando Rodriguez S. over 8 years ago in reply to cobsonchael

TI__Guru* 84915 points

Hi,

There shouldn't be a problem with the codec inputs. Regarding the outputs, the datasheet mentions a minimal load resistance at the line output and headphone output. The line output cannot handle this impedance since it supports 10kohm as minimal resistance. There won't be a problem with the headphone line. It supports a 16ohm minimal load resistance.

http://www.ti.com/lit/ds/symlink/tlv320aic3106.pdf#page=6

Best regards,
Luis Fernando Rodríguez S.

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320AIC3106 and POTS phone lines/telephone handset