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ADS1675REF: Fast ADC (>1MSPS) with low error (<0.5mV)

he dajiang
Prodigy 166 points
Part Number: ADS1675REF
Other Parts Discussed in Thread: ADS1299, ADS1675, ADS9110, ADS8900B, ADS8900BEVM-PDK, ADS9110EVM-PDK, ADS8910B, ADS8920B, ADS1261, ADS8688, ADS124S08

I am looking for fast ADC chip that can produce 1M sample per second with less than 0.5mV error. TI's ADS1299 is a good ADC chip widely used in EEG HW. Its error can be less than 0.1mV with 250 sample rate. However its max sample rate is only 16k.

ADS1675 seems a good choice. I wonder if there is any breakout board for it. Its evaluation board is rather expensive $499.

  • +1
    TI__Guru 60375 points

    Hello,

    Additionally take a look at the 18-bit, 2MSPS ADS9110, and the 20-bit 1MSPS ADS8900B.  Both devices feature more cost-effective EVM solutions as well and are popular devices for high resolution measurements. 

  • 0 in reply to Collin Wells
    Prodigy 166 points

    thanks for the info.

  • 0 in reply to Collin Wells
    Prodigy 166 points

    For the ADS9110 evaluation board (https://www.ti.com/tool/ADS9110EVM-PDK), is it possible to use my own MCU to communicate with ADS9110?

    It seems I can only test it with TI-provided software, isn't it?

    I wonder how I can use it in my own testbed, where the central controller is a MCU.

  • 0 in reply to he dajiang
    TI__Guru 60375 points

    Hello,

    The man focus of all of our precision ADC EVMs is to easily evaluate the performance of these complex ADC systems.  We try to make things easy to connect up externally as well, but the ADS9110 is admittedly not so convenient to use with an external controller because a standard row of SPI headers was not included like it is on the ADS8900BEVM-PDK.  You would have to solder small wires to the resistors and connect those to your controller to use the ADS9110EVM-PDK.  Maybe the ADS8900BEVM-PDK is a better fit and you can use the ADS8900B EVM GUI to mimic performance of an ADS8910B (18-bits) if you're only interested in 18-bits. 

  • 0 in reply to Collin Wells
    Prodigy 166 points

    What do you mean by mimicking performance?

    With ADS8900BEVM-PDK, can I use my own MCU to communicate with 8900B to get ADC reading?

  • 0 in reply to he dajiang
    TI__Guru 60375 points

    Hello,

    What do you mean by mimicking performance?

    -The ADS8900BEVM GUI software can operate the 20-bit ADS8900 in a "short-clocked" operation where only 18, or 16-bits are read out.  Since the performance of the ADS8910B and ADS8920B are quantization noise limited the performance of a short-clocked ADS8900B will mimic the performance of the other resolution devices. 

    With ADS8900BEVM-PDK, can I use my own MCU to communicate with 8900B to get ADC reading?

    -Yes, you will need to apply power and the digital signals externally through the male header pins you can see in the image of the board we provided. 

  • 0 in reply to Collin Wells
    Prodigy 166 points

    Do you mean the SPI interface as showed in below image:

  • +1 in reply to he dajiang
    TI__Guru 60375 points

    Yes, you will disconnect the PHI (PA007) motherboard and apply power to the DVDD/LDO_IN test points (please review schematic) and the digital signals will connect to the J4 jumper you've highlighted. 

  • 0 in reply to Collin Wells
    Prodigy 166 points

    Both 8900 and 9110 do not have programmable gain. Since the measuring range of those two ADC are from 0 to at least 2.5V,  but in my application, I need to measure differential voltage from 0 to 300mV, there is a big range not utilized. Collin, what is your comment?  

  • 0 in reply to he dajiang
    TI__Guru 60375 points

    Hello, The devices have high resolution so you may not need to use the full input signal range.  Otherwise you need to build an external amplifier circuit.  At the time of this posting we don't have a great offering for high-speed, high performance ADC cores with integrated PGAs for low-level signals.  The low-level signal PGAs are typically found in lower-sample rate Delta-Sigmas (ADS124S08, ADS1261), and the SARs with PGAs are typically attenuating PGAs (ADS8688, ADS8588), not for smaller input signals.