dear sir,
we are testing with INA125 with single ended supply without load cell but the circuit not working properly .
we could not get the gain as specified.some range its reading value not proportional i attaching circuit please help us .
we want the circuit withot load cell as input .we connect input as voltage source please reply as sson as possible
thankyou
Hi Lijo,
When using a single power supply the INA125 minimum common-mode voltage is about +1 V above ground. Pin 7 (-In) is set to zero volts and pin 6 (+In) can be as low as 1 mV per your schematic. Both are lower than the minimum common-mode voltage (CMV) limit and the amplifier will not be operated in its linear operating range. The CMV range for Vs = +5 V is the upper left region in the data sheet graph. The same lower limit is applicable to Vs = +12 V.
The easiest solution for resolving this issue is to use dual (+/-) supplies. The negative supply could be a negative power supply line, or be provided by a boost/buck voltage regulator such as the LM2674 that creates a negative voltage from a positive input voltage.
Regards, Thomas
PA - Linear Applications Engineering
