AD7768 : 8 CHANNEL ADC CAN SUPPORT SINGLE END - BIPOLAR INPUT.

Hi All ,

I have an requirement to convert the 8 channel analog input (Single ended - bipolar) signal with the range of 10Vpp, The waveform will be sin, ramp, square,and Sweep.

Hence I am planing to use AD7768. In this I need a clarification of following points:

1. I have 8 channel single ended bipolar signal inputs (10Vpp, +/- 5 ), So I will connect this signal to the correspoding port of (AIN0+ to AIN7). My question is, May I Ground it the remaining ports of AIN-0 to Ain7- ?

2. My input signal should support (+5V to -5V , 10Vpp), so in REF1- and REF2- may I connect to Ground or -2.5V should give ?

3. If I ground the REF1- and REF2- , The AD7786 support the input signal swing 10Vpp?

4. Even though My Signal is single ended bipolar , Is there I want to make this signal to converted into differential bipolar (True Biploar signal)?

Please clarify the points as soon we are going to finalise the design stage.

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  • Hi NiallM,

    Thank you very much for your inputs !!!

    I am going with AVDDx, REF+x = +2.5V  using  ADP7118 ; and AVSSx , REF-x = -2.5V using  ADP7183ACPZN2.5-R7

    Is this LDO Current is enough for AD7768 Supply ?

    I have an rearranged architecture of my 8 Channel Receiver card.

    Before the architecture is :

     

    Re-arranged architecture :

    Can you give me your clarification of following parts.

    1.        AD826: I am going to attenuate my signal ranges from 10Vpp to 5Vpp (+/-5V to +/-2.5V ). By selecting RF /Rin with inverted output (Example:  RF = 1K ; Rin 2K = -0.5 Gain). This Output is fed to the input of another channel of  AD826. Hence I will get +/-2.5V attenuated signal.

            Is this right way of attenuate my signal range ? or do you have any recommended part for this design?

    1.         ADA4922-1 This attenuated signal is fed to the ADA4922-1 to convert the single ended bipolar signal to   differential bipolar signal and fed to the ADC (AD7768) input.

    This single ended to differential end conversion is there right part to do the conversion instead of you recommended LTC6363.

     

    Please confirm may I go ahead with this part ?

     

    Thanks and Regards,

    Mohamed Sidiq.H

Reply
  • Hi NiallM,

    Thank you very much for your inputs !!!

    I am going with AVDDx, REF+x = +2.5V  using  ADP7118 ; and AVSSx , REF-x = -2.5V using  ADP7183ACPZN2.5-R7

    Is this LDO Current is enough for AD7768 Supply ?

    I have an rearranged architecture of my 8 Channel Receiver card.

    Before the architecture is :

     

    Re-arranged architecture :

    Can you give me your clarification of following parts.

    1.        AD826: I am going to attenuate my signal ranges from 10Vpp to 5Vpp (+/-5V to +/-2.5V ). By selecting RF /Rin with inverted output (Example:  RF = 1K ; Rin 2K = -0.5 Gain). This Output is fed to the input of another channel of  AD826. Hence I will get +/-2.5V attenuated signal.

            Is this right way of attenuate my signal range ? or do you have any recommended part for this design?

    1.         ADA4922-1 This attenuated signal is fed to the ADA4922-1 to convert the single ended bipolar signal to   differential bipolar signal and fed to the ADC (AD7768) input.

    This single ended to differential end conversion is there right part to do the conversion instead of you recommended LTC6363.

     

    Please confirm may I go ahead with this part ?

     

    Thanks and Regards,

    Mohamed Sidiq.H

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