PGA4311

luis suarez

Other Parts Discussed in Thread: PGA4311

Hi, after mi last mesage We finish other proyect and I will satrt to work with the pga4311 to made a gain control of our desing.

After reading the data shhet I have some easy questions, to conect at the output of each chanels of the atenuator, Iread taht is possible to conect transducers with impedance lower than 600ohms. I think taht the op inside made the impedance conversion. I think taht is possible to conect the transducer directly, is that correct??

Other thing, with this device we will have a dinamic range of 127db, we need 120dB but we need another extrernal +-10dB to fit a calibration the spl db (sound presure levels) with HL db (hearing level db) there is a special iso correction values.

The imput will be an analog audio.
In case taht we use 2 chanels one for the ateanution and the output to the imput of other for the other for the calibratión factors, I think it will be better sound with only one adc and dac conversión. What do you think about it? Any component recomendation ?

And for finish, Is possible to now the specting year to manufactury stop of the pga4311? is good for a new desing??

Best regards abd thaks for all

Luis

over 11 years ago

0 Don Dapkus over 11 years ago

TI__Guru**** 189401 points

Hi, Luis,

I have asked my colleague to comment on your post.

-d2

0 Ian Williams over 11 years ago

TI__Mastermind 27715 points

Hello Luis,

I do not recommend connecting a transducer with impedance lower than 600Ω directly to the output of the PGA4311. The THD+N performance decreases quickly as the load impedance decreases below 600Ω, since the output stage of the PGA4311 can no longer deliver the required current to achieve the correct output voltage. If you have a low-impedance load, I recommend placing a high-output-current buffer stage at the PGA4311 output.

I'm not sure I understand your second question about dynamic range. The PGA4311's typical dynamic range, with the input grounded and gain = 0dB, is 120dB. I don't know of a way to achieve higher dynamic range as long as this device is in your audio signal chain.

The PGA4311 will not be discontinued at any time in foreseeable future. It is TI's policy to not make any parts obsolete as long as customers are purchasing them.

Best regards,

Ian Williams
Linear Applications Engineer
Precision Analog - Op Amps

0 luis suarez over 11 years ago in reply to Ian Williams

Prodigy 140 points

Hi Ian, Thank you very much for your fast answer.

About mi questions:

As I told you I will connect directly our transducer to the output of the pga4311. Transducers of 8 and 3 ohms Yes 3.

I understand that you recomend me to connect before something to equal the impedance of the output?? like OP inverter. Or do you have any special device for that??

The second question:

We will wont to work with all of the dynamic range of the atenuattor to work with it. But we will need to calibrate the attenuation values to different levels for different sources (frecuencies for example). In some cases we will need +10 to -10 dB to calibrate the system, after that we will use all the dianmic range of the pga4311 CALIBRATED.

To made this calibration I think in other channel of the 4311 but I don´t like to made 2 ADC and 2 DAC do you think that the second conversion worse the quality of sound??It would be better to made this calibration before the 4311 with an analog amplifier??

any recomendation?

Bets regards and thanks for your help

Luis

Audio

Audio forum

PGA4311