wats the use of pin no. 5??? and when to use it??? and how to use it???
Hi,
Pin #5 is the V reference pin.
Assume you wanted the Vout of the AD620 to be 0 volts when there is no differential input signal on its inputs,pin2 and 3, you would connect Vref to 0Volts of the circuit
If you wanted to offset the Vout from 0V , when there is no differential voltage input between pins2 & 3 you would connect Vref to a +/- voltage. A +1V on pin5 would make the Vout +1V, a -1V on pin 5 would make the Vout = -1V.
Note: the Vref voltage must be derived from a low impedance source.
So the 'amplified' differential voltage between pin2 & 3 would be superimposed on the Vref voltage value.
Pin #5, should not be left floating, ie : it must be connected, otherwise the AD620 will not work as expected.
For the
Rg,gain resistor value look at page #13 of the AD620 datasheet, clip attached.
If you dont follow , please ask.
Note: the AD620 is designed to work with dual supply voltages.
EDIT: added an image to show the effect of Vref