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ADC1173EVM: ADC1173EVM

Guru 13485 points
Part Number: ADC1173EVM

Got below question:

I'm using the EVB ADC1173EVM and I'm having important issue.

 

I'm supplying 5V, from power supply while supplying my own 3Mhz clock with output buffer disabled.

 

Power consumption is 5*20mA = 0.1W (without clock provided)

And 5*14mA = 70mW while supplying clock of 3Mhz.

 

  1. Why power consumption is higher without clock ? it should be other way around..
  2.  According to Datasheet it should be 33mW @15Mhz. so I expected it to be around 10mW @3Mhz.

 

  • Hi eli
    We have received your question. One of our ADC experts will provide a more detailed response shortly.
    Best regards,
    Jim B
  • Hi Eli,

    If you would like to measure power consumption of ADC only, you will need to supply 3V externally to ADC. Please do the following:

    Ensure FB4 is depopulated.
    Remove FB3
    Provide 3V on TP2.
    Remove JP7
    Populate JP3
    JP2 Shunt 2-3
    JP4 Shunt 2-3
    JP10 Shunt 1-2

    This should provide a more accurate power measurement.

    Best Regards,

    Dan
  • Hi

    According to the customer the EVM is not same as in its user guide: 

    http://www.ti.com/tool/ADC1173EVM?keyMatch=adc1173&tisearch=Search-EN-Products

    Now the EVM is not working,look that he is damaged.We order a new one

    can you advise the values of the two resistors in yelow?

  • Hi Eli,

    R30 is 4.22k and R26 is 1.1k, which should already be installed.

    The main reasons the current/power consumption is so high is due to the resistor dividers for the analog and clock inputs. Replace R8 and R9 with 10k resistors and the current should drop by 50%. There are some other resistors that can be scaled up in value that will further reduce idle power consumption on the evaluation module. I would also suggest removing the resistors R11 and R12 to reduce the 3.3V rail to 3V. This is within tolerance for the ADC and all other supporting components.

    With this configuration [disabling the onboard crystal (JP1 2-3)and connecting an external disabled clock through the splitter U3 (JP2 2-3)], I am drawing 12 mA on my 5V supply.

    When I enable the 3 MHz external clock, I draw 15 mA.

    When I enable a 2 MHz, +4 dBm, analog input, I draw 16 mA of current.

    When I enable the 15 MHz external clock (+8 dBm) , I draw 18 mA.

    When I enable a 1 MHz, +4 dBm, analog input, I draw 24 mA of current.

    I am collecting data for the next revision of this EVM, so please let me know if there are other concerns.

    Best Regards,

    Dan