Apparatus and method for analog-digital converting

A method of operating a communication device comprising a radio frequency integrated chip (RFIC) with a successive approximation register analog-to-digital converter, the method comprising:

• modulating, by a modem of the communication device, a baseband signal according to a communication scheme for wireless communication;
• converting, by a most significant bit digital-to-analog converter (MSB-DAC) of the RFIC, a first digital signal into a first analog signal;
• converting, by a least significant bit digital-to-analog converter (LSB-DAC) of the RFIC, a second digital signal into a second analog signal;
• measuring, by a comparator of the RFIC, a voltage value corresponding to a combination of the MSB-DAC and the LSB-DAC;
• outputting, by the comparator, a result of a comparison of the measured voltage value with a sample voltage value;
• analog-to-digital converting, by a controller of the RFIC, a first measurement value output from the comparator by applying a reference voltage to a unit capacitor of the MSB-DAC to generate first measurement data;
• and
• analog-to-digital converting, by the controller, a second measurement value output from the comparator by applying the reference voltage to the LSB-DAC to generate second measurement data.