INA310A-Q1: INA310A3

Vincent Marsaud

Part Number: INA310A-Q1

Good Morning.

I'm using INA310A3 for mesuring current between 50mA and 2A.

By measuring with a scope, the INA310A3 ouput voltage, I have a 7% error (264mV for a real current through the shunt of 120mA, checked with a serial amperemeter).

The 0,02ohm shunt has an accuracy of 0,5%.

Taking into account the 0,05% shunt accuracy into LTspice simulation, the output voltage error value is 1,1%, which seems to be more correct.

The schematic is the one above.

What may cause this 7% error ?

Thanks per advance.

over 1 year ago

0 Javier Contreras4 over 1 year ago

TI__Mastermind 32860 points

Vincent,

I believe if you are measuring high then it will most likely be your layout. If this is not the case please post your layout to continue debug. Also include your Vout load.

See this post to go through debug process: https://e2e.ti.com/support/amplifiers-group/amplifiers/f/amplifiers-forum/1331863/ina290-incresing-voltage-offset-on-current-sense

This video also goes through the layout issues https://www.ti.com/video/6243578140001

Also just from Vos calculations at max you will get and error at the output of 5mV = 50µA(Vos) x 100(Gain). The models usually do typical value which would be 5x smaller. The worst case for VOS is 5mV/240mV * 100 = 2.08%

Regards,

Javier

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INA310A-Q1: INA310A3