Abstract: An A/D converter including first and second A/D converters and a recombination module. The first A/D converter receives an analog input signal, converts the analog input signal to a first digital signal, and includes a successive approximation module, which performs a successive approximation to generate the first digital signal. The second A/D converter converts an analog output of the first A/D converter to a second digital signal. The analog output of the first A/D converter is generated based on the analog input signal. The second A/D converter is a fine conversion A/D converter relative to the first A/D converter. The second A/D converter performs the delta-sigma conversion process and includes a decimation filter that suppresses noise which reduces amplification and power consumption requirements of the first A/D converter and performs a delta-sigma decimation process to generate the second digital signal based on the analog output of the first A/D converter.