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ADAU1361, ADAU1761 - input differential level

Question asked by Sasa on Jun 27, 2012
Latest reply on Jul 3, 2012 by BrettG

I use differential inputs LINP/LINN and RINP/RINN. Full scale is 2.83Vpp (AVDD=3.3V, 0dB – pg.5 of datasheet ADAU1361). But on page 31 of datasheet in division “ADC Full-Scale Level” said about -1.38dB.

 

What codes I get from ADC, if I apply on LINP=2.5+2.83/2 and LINN=2.5-2.83/2?

Registers setting:
R8=R9=0100011 (Differential Input Volume 0dB),
R11=0 (ALC off),
R20=R21=0 (Input Digital Volume 0dB)


It will be 0x7ffff or 0x6d3262?

 

If I apply a little above 2.83V: LINP=2.5+2.84/2 and LINN=2.5-2.84/2, will be it clipping? What codes I get from ADC in this case: the same (0x7ffff or 0x6d3262) or 0x6d9529?

 

If I set R8=R9=00111111 (Differential Input Volume -0.75dB), what input full-scale level I get? It will be 3.085Vpp and the same ADC codes (0x7ffff or 0x6d3262)?

 

There is parameter for differential PGA input on pg.5 “Gain Error -14%”. What does it mean (-14%=-1.38dB)? But for single-end input “Gain Error” is -12%...

 

Alexander

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