You can simulate the a Av=+1 feedback config, and input a vcc/2 to +ve input. If your opamp have systemic offset, you will read it on -ve input. For random offset, you better to model it from the principle.
the way you can do that is to sweep your differential input from say about -0.5V to +0.5V, your offset should fall within this range. the output (Vout vs Vsweep/in) will look like a step. Vsweep/in @ Vout=0 is your offset voltage Vos. so long as in the graph, the point vin=0 falls in the linear region of the step, you will have reasonable results.
hi everybody,
thanx for your help, i would like to till MY OP-AMP for Track and Hold T/H application that deal with small term of capacitance.
any way my T/H work as well but still ineed to increase its SFDR.
this measurment of the OP AMP is so complex for me especially CMRR bcz my OPAMP is fully differential .
still i didnt get the solution as well for my case. if there any datasheet or notes can help pls suggest it to mt
regards
since your opamp is ideal, you will get nothing, in practice, we gorund the inputs of the opamp and check the outpur, I believe it is a good idea to model the disturbing effect via a source
wire ur opamp as vtg follower connect i/p to ground . the vtg of o/p shuld be zero . but due to offset it will not be zero . this will be of very less measure it with some precesion measuring instrument
wael_wael said:
thanks, but still i need the circuit which be used for measuring the offset, and how to do that.
regads
you may connect you OPAMP as a voltage follower, then sweep the dc voltage at the postive input stage, and check the difference of output voltage with your input voltage .
the offset will be showed by their difference