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Original question:

ADS1147 IDAC output compliance seems to be about 2.6V with 5V supply. What did I mis

ADS1147: No Output

Rahul Vijayan
Prodigy 40 points

Part Number: ADS1147

Hi, 

I am a beginner and is involved in a board testing and I came across the ADS1147 IC (ADC with PGA-20 pin) where the REFP0 and REFN0 are not connected, instead the VREFOUT is connected to ground through a 10 uF capacitor.( from the datasheet I found that in 1147 we can internally set the REF, may be this is used for that,IDK).VREF is also connected to ground. AVDD,DVDD is 3,3V and AVSS is 0v.

The input coming from a Load Cell and is connected to AIN0 and AIN1, It is about 1.86 but is having a mV range difference between the two.The problem is that voltage at VREFOUT and DOUT is showing only in mV range.From datasheet I found it should a minimum of 0.5V. The output from this IC is needed in serial communication by SPI. (DOUT of 1147 to MISO, DIN of 1147 to MOSI).  The SCLK and nCS are showing the required signals.Is there any need for any enabling of any pins? 

Can anyone suggest what may be the problem.

Thanks in advance.

  • 0
    TI__Guru** 100335 points
    Rahul,


    This is similar to another post from here:

    e2e.ti.com/.../777510

    I think you both are from the same company, if you're working together, you can work off the same thread. However, as I mentioned in the response, the internal reference defaults to an off position but must be enabled through a register. I also gave a quick start check so you can see if the device is converting.

    Read through the post and see if it helps.


    Joseph Wu
  • 0 in reply to Joseph Wu
    Prodigy 40 points
    Thanks, it worked.
    The problem was , two resistors was misplaced at the RESET pins, so that pin was not showing the required value. After having soldered them correctly, VREFOUT and DOUT was obtained.

    And yes, the person with similar post is my friend and we're working together.
    Thanks again.