one of our customer designed with QN9090 BLE MCU.
and they want to exact current sink value of QN9090's GPIO in case of input mode.
I thoroughly checked QN9090 datasheet/RM, but there is no explanation regarding this.
Hope you are doing well. The GPIO pins have the IO characteristics listed on Table 17 of the Datasheet (QN9090(T)/QN9030(T) DS), there you can find specified the input leakage current (Typ 4.5 nA).
Hope this helps.