• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 2 answers
  • Subscribers 30 subscribers
  • Views 118 views
  • Users 0 members are here
Support feedback
Options
Options
Related

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.

PCM1718: E

Pradeep KS
Prodigy 25 points
Part Number: PCM1718

Tool/software:

Hi team, 

We are working on addressing the Obsolescence in which PCM1717 is obsolete and we are using PCM1718 as a alternate. 

The design used for PCM1717 is retained, and same is used for PCM1718. But we see the noise gets increased in the new PCM1718 IC. 

  • 0
    TI__Mastermind 30391 points

    Hello Pradeep,

    Although the specs tale  in datasheet look identical for both of them , by looking at the dynamic performance plots I can see the performance difference. For example 

    The plots of DR and SNR (page 4 in datasheet) @ 4V    for PCM1717  indicate DR=96dB and SNR ~99dB  but for  PCM1718  they are  DR=95dB and SNR ~98.5dB.

    Similar observation holds for THD+N . Note also the range of the plots for PCM1718 is 4V to 5.5V  but PCM1717 is 3.0V-5.5V

    So your observation seems valid. If your applications requires lower noise, we can take a look at other alternatives but for sure you have to change your board layout  as pinouts will be different.

    Regards,

    Arash 

  • 0 in reply to Arash Loloee
    Prodigy 25 points

    Thanks Arash, 

    PCM1717 has both software control and hardware control, where as PCM1718 has only hardware control. 

    In our pervious design we were using PCM1717 in software control mode, where pin 16 and pin 17 is configured to additional functions along with the de-emphasis for a frequency. 

    But PCM1718 has only hardware control and i need to de-emphasis at low frequency. (32KHz to 40KHz). ..and there is no software control. As per data sheet its adjusting the PIN 16 and 17 to either 5V or 0V. 

    If i do this in hardware control mode, there is a fluctuation in the noise at very high level. 

    Also can you please suggest a alternative for PCM1717, with same foot print, software and hardware control.  

  • 0 in reply to Pradeep KS
    TI__Mastermind 30391 points

    Hi Pradeep

    Yes, The Hardware control version of this device (1718) has a limited De-emphasis options:

    As I mentioned above, we do not have a pin to pin compatible device and you have to go with a totally different pinout and even package.

    If you  do not want to go with PCM1718, let me know if you need any help to find a suitable device for your application.

    Regards,

    Arash