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ADS1220 vs ADS1247 for load cell application

user4229653
Prodigy 10 points
Other Parts Discussed in Thread: ADS1220, ADS1247, ADS1262, ADS1256, ADS1232

Hi:

I am targeting an application that involves an ADC to acquire samples from a load cell, at about 1000SPS. 

I have narrowed down the ADCs that would potentially be applicable to my application to the ADS1220 and the ADS1247.
These are the parameters of the application:

- What is your input signal: differential, resistor bridge 350ohms
- Reference voltage: internal
- Supply voltages: 3.3V digital, 3.3V or 5V analog (will test both in situ)

Looking at the datasheets for the 120 and the 1247, comparing for the same analog supply, sample rate and PGA, it seems the 1220 has an edge on the 1247 on all parameter except offset drift vs temperature. I would like to confirm this assessment.
Also it looks like the 1247 offers more features (GPIOs etc) and may be geared towards a self contained analog processing unit (as opposed to a full microcontroller assist with the 1220). The 1220 also seems to be much more power savvy than the 1247.

Overall, what application is each device targeting?

Regards,
JS

  • 0
    TI__Guru** 113765 points

    Hi JS,

    Welcome to the forum! Generally speaking our current best load cell parts will be the ADS1232, ADS1256 or the ADS1262.  Apparently you will need faster speed than the ADS1232, and the ADS1256/ADS1262 will be higher cost than the ADS1247 or ADS1220.

    For the most part the ADS1247 will outperform the ADS1220.  However there are issues with the ADS1247 as it relates to ratiometric measurements at excitation voltages to the load cell that are the same as the AVDD supply voltage.  In other words you cannot use the AVDD supply as both the reference and excitation for the load cell.  You can do this however with the ADS1220 which may in the end have less noise/drift in the measurement.

    One further mention is that you will require just as much effort from the microcontroller for both the ADS1247 and the ADS1220, so I'm not quite sure what you mean with the ADS1247 being more 'self contained'.

    As far as what the measurements we are targeting for the ADS1247 and ADS1220, they are low speed data acquisition for sensors that do not change quickly. Current, voltage, temperature, and bridge sensors like load cells and pressure sensors to name a few.

    Best regards,

    Bob B