Is the schematic correct ?  the two outputs are connected  and the two inputs

Where do I find the other end of "FILTER OUT" ?

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  • U6-A, U6-B, and UC-6 are the same dual opamp IC. That circuit is generating a 2.5V reference voltage, likely used to bias the ADC's input.

    FILTR is the capacitor connection for the AD1936's internal voltage reference. See the datasheet for that part.

  • Thanks .So it is not connected to elsewhere in the circut ?

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    •  Analog Employees 
    on Jun 15, 2021 2:51 PM in reply to izhmel

    Hello Izhmel,

    There is a lot of vagueness in this post. What are the schematics from? 

    After doing some looking I see it is from the EVAL-ADAU1452REVB

    The outputs of U6 net names pretty much describe what they are used for. For the ADC buffer op amp reference. 

    The FILTR output of the AD1938 is used only internally. It comes out on a pin so large bypass capacitors can filter this reference voltage. It is not and should not be used for anything else. If the internal Common Mode (CM ) voltage is desired for direct coupling the DAC output filters then the CM pin, pin 38, can be used but it is recommended to buffer it using a voltage follower. 

    Dave T

  • I got it from here EVAL-ADAU1466Z User Guide (Rev. 0) ( .

    Is the ADAU1452 compattable with the ADAU1466WBCPZ300 , is there any diffrence , can they be use on the same PCB , are the PCB pins the same ?

    Thanks in advance 

  • 0
    •  Analog Employees 
    on Jun 15, 2021 4:21 PM in reply to izhmel

    Hello izhmel,

    Yes, they are pin and software compatible. 

    The ADAU1452 was produced first and so the ADAU1466 was designed to be compatible with the 1452. So any 1452 program will run with no changes and the pinouts are the same. 

    The 1466 has a few features and specs that are different. So if a 1466 program is using features that are not in the 1452 then it will be an issue. 

    Many of the added features of the Sigma350 parts are in the 88 pin versions like the 1467.

    Here is  list of the top of my head. Always refer to the datasheet if there are questions.

    The 1466 has more data and program memory.

    The SPDIF ports can run up to 192kHz fs

    The I2C port can operate up to 1MHz. 

    These are the most significant changes. 

    The 88 pin parts have even more differences but this is not what you are asking about. 

    Dave T