I am using AD5522 as the PMU. I had purchased an evaluation kit for AD5522 and designed a prototype using AD5522 for my products. During development, I am trying to source 5uA using 5uA current range with voltage clamp programmed at approximately 11.25V (max). I connected a 2MOhm resistor as a load. However, I would not be able to source up to 5uA. The PMU channel device does not seems to goes into voltage clamp as the voltage across the load is only around 8.4V. With 8.4V across 2MOhm load, the effective current is only 4.2uA. Even if I try to increase the FIN to hex value 0xFFFF, the output current still could not hit 5uA even though the voltage across the load is less than the clamp voltage.
Please advice. Thank you.