Question
Hi CIC team,
Currently, a customer is using AD711JRZ and they have a failure rate of 80% in the production of printed circuit board. IC U 30 in conjunction withC88 has a tendency to oscillate.
The circuit itself is unchanged for years. An exchange of AD711 elder components eliminates this error. Similarly, the capacity reduction of C88 one.g. 1nF. Do you know that behavior? What do you recommend?
Answer
That capacitive load is quite high for the amplifier. Please refer to page 11 in the data sheet where it mentioned to use a load resistor when thecapacitive load is exceeding 1500pF. This could be the reason for your oscillations. Find below the recommended circuit for driving the capacitiveload.
Also, try reducing the resistors, RN1-A and RN1-B to 5KOhms and also the capacitor to 50nF. I hope this reduction would give you the expectedresults. If not, please reduce them further.