Typically, if an external op amp is used to scale the ADC inputs an external analog multiplexer is also required to select the various inputs to be applied to the op amp input. The RX ADC block allows an external op amp to be connected after the input analog multiplexer so the need for an external multiplexer is eliminated. The multiplexed analog input is output on the ANEX0 output. This signal is processed by the external op amp or other circuitry then input to the conversion circuit in the MCU using the ANEX1 pin. Once the appropriate control registers are configured, scanning inputs and reading conversion results is the same as when the external circuit configuration is not used. However, the conversion time is increased by the latency of the external circuits. This feature is not supplied in the RX62 group. The device hardware manual should be checked to see if this feature is supported for a specific device.