[sdiy] SOIC audio ADCs & dsPIC33F devices with codec interfaces not shown as such in the selector chart

[Robin Whittle]

Hi Eric,

Thanks for the link to your project:

  http://ebrombaugh.studionebula.com/synth/dsPIC_sp/index.html

Here is a correction to what I wrote about the Wolfson ADCs - I wrote
that the 14 pin device had no advantages over the 8 pin device.

  http://www.wolfsonmicro.com/products/adcs/

The 8 pin device has a poorer distortion figure, but a better signal to
noise ratio.  They both output 24 bits, but the lowest 8 or so bits of
this would be noise:

         SOIC pins   SNR dB    THD db

  WM8738        14       90    -87
  WM8783         8       95    -83

Both have a maximum signal level of 1V RMS, but the 14 pin device needs
its analogue supply to be 5 volts to accept this.  If it runs at 3.3
volts, then the maximum signal level would be less.  The 8 pin device
uses 3.3V for its digital and analogue supply.

I had not heard of Wolfson before.  I never expected to be buying DACs
or ADCs from a company headquartered in Edinburgh - I always regarded
this an art more at home in the USA (Burr Brown and Crystal - who I
think pioneered sigma-delta ADCs and DACs with AKM) and Japan (AKM).

 - Robin