I'm working with the AD7746 evaluation board, but I'm having problems to couple the extending of the capacitive input range of the AD7745 / AD7746 (application Note: AN-1585), I did the calculations as mentioned in sheet 3 of AN-1585 datasheet, but when the program is running only marks me the maximum value and does not change when I modify the capacitance. (It is for a level sensor).
The capacitor I am using is 150pF empty, I put a capacitor in series to leave a capacitance of 17pf and be able to measure it only by adjusting the CAPDAC as mentioned in datasheet 21 of AD7746, but the SW only shows me a value of -4,096 that does not change even if I modify the capacitance only changes to maximum (+ 4,096pF) when the capacitor in short circuit.
How much capacitance can be adapted using the extending capacitive input range (AN-1585)?
Thanks in advanced
I will consult the product owner about your question and get back to you as soon as possible.
Can you advise me on the Resistor values you are using in Circuit? Also please let me know the Register Values that you have programmed. Also what do you mean by 150pF empty?
Wa$iM said:Can you advise me on the Resistor values you are using in Circuit?
Hi, I use 100K and 125K
Wa$iM said:Also what do you mean by 150pF empty?
I implemented a level sensor when the capacitive is empty, I mean the dielectric is air are 150pF, when the dielectric is diesel is 280pFI want to see how to increase the capacitive on Eval board AD7746EB.