Now I have a project about air monitoring.I use four electrochemical sensor. So I use four LMP91000 in my PCB.I marked them as AFE_A,AFE_B,AFE_C,AFE_D.
I set same preference to LMP91000 through I2C in order to test AFE:3-lead mode,extern reference,zero voltage is 20% Vref(Vref=2.5V),Rload is 100Ω,Rfeedback is 120kΩ.
It seems that two of these AFE are normal.But others are unnormal. VOUT(A)=0.5V,VOUT(B)=0.5V,VOUT(C)=0.86V(uncertain,it's changing),VOUT(D)=0.95V(uncertain,it's changing). VOUT(C)&VOUT(D) are unstable.when I touch VOUT pin or measuring VOUT pin by multimeter,the voltage is down to 0.2V(uncertain).
Who can tell me something about probable causes...thanks
