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DAC81402: DAC81402 is not giving output voltage

Sooraj Surendran
Prodigy 110 points
Part Number: DAC81402


Tool/software:

Hi Team 

We are using DAC81402 in one of our design and configured the DAC as per datasheet. We are able to read the configuration set values in the registers through oscilloscope. But Output voltage is not coming. Please check our schematic .  

  • 0
    TI__Mastermind 42273 points

    Hi Sooraj, 

    Sanjay will review and provide some feedback soon. 

    Best,

    Katlynne Jones

  • 0
    TI__Expert 5450 points

    Hi Sooraj,
     
    Please check data sheet recommended power supplies values for the DAC81402.

    There are few problems in the schematic as mentioned below - 
    1. DVDD is 3.3V and it should be between 4.5V to 5.5V.
    2. VSENSEN (A/B) - should not be floating but either between  -12V to 12V or GND
     
    Thanks,
    Sanjay 

  • 0 in reply to Sanjay
    Prodigy 110 points

    Hi Sanjay 


    Connected the VSENSEN(A/B) to ground and DVDD TO 5V. Still we are facing the same problem like irrespective of the DAC Configuration , output voltage is going keep on increasing. We would like to know the reason for this. 

  • 0 in reply to Sooraj Surendran
    TI__Expert 5450 points

    Hi Sooraj,

    Please provide the following details to help you in debugging the issue - 

    1. Measure all the power supply voltages on the hardware and report that to us.
    2. Provide the read/write command that is being used to get the DAC VOUT on any of the channel A or B.
    3. Confirm if that OUT and SENSEP line are shorted on the hardware for both the channel A & B, check in manually and then confirm.

    Thanks,
    Sanjay 

  • 0 in reply to Sanjay
    Prodigy 110 points

    Please see the below response:

    1.Measure all the power supply voltages on the hardware and report that to us.

    External Reference Provided : 2.5V

    IOVDD :3.3V 

    DVDD : 5V

    2.Provide the read/write command that is being used to get the DAC VOUT on any of the channel A or B.

    ...

    3. Confirm if that OUT and SENSEP line are shorted on the hardware for both the channel A & B, check in manually and then confirm.

    Yes shorted with Zero ohm resistor 

  • 0 in reply to Sooraj Surendran
    TI__Expert 5450 points

    Hi Sooraj,

     
    1. And what about the AVDD and AVSS power supply values ? 

    2. Provide the read/write command sequence that is being used to get the DAC VOUT on any of the channel A or B. - missing details ?
     
    Nonetheless, if power supples are as per recommended values in the data sheet. Follow the below write command to get the voltage on the DAC outputs

    a) Write 0x0A84 in SPICONFIG (0x03) -  to power-up the DAC81416 device 

    b) Write 0x3F00 in GENCONFIG (0x04) - if you are using internal reference, else ignore this

    c) Write 0x0000 in DACPWDN (0x09) - to power-up the individual DAC channels

    d) Write 0xFFFF in DACn_DATA (n = 0x11 or 0x12) -  to configure the DAC A or B channel outputs to 5 V 

     
    Thanks,
    Sanjay