Hardware/Mezzanine/audio AD-DA

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(Audio AD/DA mezzanine board)
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== Input range ==
 
== Input range ==
  
The board input signals are brougth to differential op-amp circuits with
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The board input signals are brougth to a first stage of differential op-amp circuits with:
 
* <math>R_{15} = R_{17} = R_{16} = R_{18} = R_{36} = R_{38} = R_{37} = R_{39}</math>
 
* <math>R_{15} = R_{17} = R_{16} = R_{18} = R_{36} = R_{38} = R_{37} = R_{39}</math>
* <math>R_{8} / R_{17} = R_{10} / R_{15} = R_{12} / R_{18} = R_{14} / R_{16}</math>
+
* <math>gain_1 = R_{17} / R_{8} = R_{15} / R_{10} = R_{18} / R_{12} = R_{16} / R_{14} = R_{38} / R_{29} = R_{36} / R_{31} = R_{39} / R_{33} = R_{37} / R_{35}</math>
 +
* <math>pos\_offset / pos\_supply = R_{17} / R_{7} = R_{18} / R_{11} = R_{38} / R_{28} = R_{39} / R_{32}</math>
 +
* <math>neg\_offset / neg\_supply = R_{17} / R_{10} = R_{18} / R_{13} = R_{38} / R_{30} = R_{39} / R_{34}</math>
 +
 
 +
The ADC inputs range from 0 V to 5V.
 +
 
 +
The output of this first circuit is decoupled and brought to a second stage built around the in-circuit op-amp of the ADC.
 +
The gain of the second stage is:
 +
* <math>gain_2 = R_{23} / R_{21} = R_{24} / R_{22} = R_{44} / R_{42} = R_{45} / R_{43}</math>
  
 
[[Category:Hardware]] [[Category:Mezzanine]]
 
[[Category:Hardware]] [[Category:Mezzanine]]

Revision as of 13:23, 5 November 2012

Contents

Audio AD/DA mezzanine board

This board has been developed as a low-cost replacement of the high-speed AD-DA board. It features:

  • two 24-bit, 192 kHz WM8782 stereo ADCs
  • two 24-bit, 192 kHz WM8759 stereo DACs

Power supply

The supply from the connector is used to power the TL064 op amps. They can be powered between ±3.5 V and ±18V.

A TPS54227 DC/DC converter generates 6.5 V from the power supply and is followed by a 5 V regulator.

Hence, the minimal power supply range is about ±7 V.

Input range

The board input signals are brougth to a first stage of differential op-amp circuits with:

  • R15 = R17 = R16 = R18 = R36 = R38 = R37 = R39
  • gain1 = R17 / R8 = R15 / R10 = R18 / R12 = R16 / R14 = R38 / R29 = R36 / R31 = R39 / R33 = R37 / R35
  • pos_offset / pos_supply = R17 / R7 = R18 / R11 = R38 / R28 = R39 / R32
  • neg_offset / neg_supply = R17 / R10 = R18 / R13 = R38 / R30 = R39 / R34

The ADC inputs range from 0 V to 5V.

The output of this first circuit is decoupled and brought to a second stage built around the in-circuit op-amp of the ADC. The gain of the second stage is:

  • gain2 = R23 / R21 = R24 / R22 = R44 / R42 = R45 / R43
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