• State
  • Locked Locked
  • Replies 2 replies
  • Subscribers 48 subscribers
  • Views 144 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Original question:

INA745B: Gain error in rangeof 0 to 1 Amps

INA700: Gain Error below 1Amps

Darshan Moodgal
Prodigy 85 points
Part Number: INA700

Tool/software:

Hi All,

Our group has been extensively using INA226s with an external shunt resistor for many years now, we plan to move to INA700 for our upcoming project.

Our concern is ina700's ability to measure current accurately below 1Amps, in the image below taken from the ina700's datasheet the gain error below 1Amps is missing.

Could you please provide us the test data for current between 0-1Amps in steps of 50mA and it's associated gain error. Your timely input is much appreciated.

  • 0
    TI__Mastermind 32395 points

    Hello again appreciated Engineer,

    I am looking this over and will respond shortly.

    Sincerely,

    Peter

  • 0
    TI__Mastermind 32395 points

    Hello Darshan,

    The variation in gain for <1A will still remain within specification. Also please note that this plot has calibrated out offset error.

    This variation in gain error is really just a variation in linearity. However, this change in linearity is dependent upon layout and how much heat dissipation is given to the device. The more thermal conduction provided to the device, the flatter this curve will be. Overall, this curve will always be there due the inherent flow of heat from integrated shunt through package.

    Measuring <1A will probably require an offset calibration. Are you considering this?

    Also, measuring <1A will probably require averaging out noise as much as possible. So what is the minimum allowable throughput? Or what is minimum required BW? 

    Do you need to measure bus voltage (VBUS)?

    Do you have any required over-current detection times?

    Sincerely,

    Peter