INA826: INA826 Vout Issue

Hi Kai,

Sorry for the late feedback, schematic as below. Thanks.

Jackson

Hi Jackson,

can you post the schematic again?

Kai

Hi Kai,

Sorry, I re-uploaded the schematic and the measure table for your reference. 

Thanks,

Jackson

Hi Jackson,

Kai

Jackson,

Based on R115 of 5.6k, 80.6ohm R120 and 2.5V shown on your schematic, the nominal value for Vb is NOT 43mV but rather  80.6/56,080.6*2.5V = 35.8mV.  Thus, according to Vout vs Vcm plots shown above, Vb will be outside of the linear input range for REF=0 and REF=2.5V resulting in the Vout collapsing on its positive rail.

Hi Marek Lis, Kai

Thanks for your feedback. I modified the schematic( Vs=5V, -Vs=-3.3V) to meet the request as below. Could you please help to double check everything if ok ? Thank you.

-Resistance of the pt100 around 80.77ohm~154.11 ohm

-Vdiff around 0.043mV~31.38mV

-Vout around 4.33mV~3.14V

Regards,

Jackson

Jackson,

Are you really using -3.3V to power a negative rail of INA826?  If so, the circuit should work just fine on dual 5V/-3.3V supplies.

Hi Marek Lis,

Yes, I will use the 3.3V to power a negative rail of ina826 to meet the vin & vout range. Or do you have any better suggtion for the single supply of ina826 to meet my request ?

Jackson