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INA180: Sources labview

Lopez alain
Prodigy 20 points
Part Number: INA180
Other Parts Discussed in Thread: INA190

Hello,

We want to measure current on signal line with INA180 EVM and  DMM 6 ½ digit following requirements as below: 

“24mA with a minimum resolution of 1uA and accuracy of 25 ppm reading + 5 ppm full scale”.

Theoretically we can prove that it is possible to do it following respectively datasheet of INA 180 and DMM but we have some questions as regard of Aging/Endurance test results, proving INA 180 solution meets accuracy over time.  Do you have some data on that?

Rsense resistance choisen is VCS 1610Z With ultra-low TCR±0.2ppm/°C with Resistance Value  1Ω
We will maintain the work floor temperature between 22C to 28C.

How can I provide a certified uncertainty analysis (approved by 3rd party ISO 17025 accredited laboratory or other) of the entire system (resistor / amplifier / volt meter)?

Best regard 

Alain Lopez

  • 0
    Prodigy 20 points

    Can i have some aging results of INA 180 ?

  • 0 in reply to Lopez alain
    TI__Mastermind 32395 points
    Hello Alain,

    Welcome to the E2E Forum. Thanks for posting.

    You can find reliability, quality, and lifetime data for most of our parts at the "Quality and Packaging" tab in the product folder. Here is the link for INA180.
    www.ti.com/.../pinout-quality

    I am honestly not sure how to obtain a system-level uncertainty analsysis. I assume you would work with the third-party and provide your own theoretical analysis, while they determine how to calibrate your system in a repeatable manner.
    www.system-scale.com/.../labservices

    What I can say is that any analysis should involve calculating the maximum error you may see across all devices using the maximum error specifications over expected temperature range. The tolerance and drift of your shunt resistor will effectively be a gain error for INA180.

    Considering the resolution you are looking for, I would recommend looking at the INA190. It has a lower bandwidth, which results in less noise on the output which may benefit you. You can always filter noise on the output of amplifier with passive RC filter or active filter. Output noise is calculated as follows:
    Vout [mV peak-peak] = Gain*en*6.6*SQRT(BW*Kc)
    Gain = device gain
    en = inherent input noise spectral density [nV/√Hz]
    BW = bandwidth of device [ Hz]
    Kc = brick-wall correction factor

    You can learn more about noise calculation here:
    training.ti.com/ti-precision-labs-op-amps-noise-1

    Best,
    Peter Iliya
    Current Sensing Applications