Multiple input analog-to-digital conversion apparatus and radio receiver using the same

A multiple input AD conversion apparatus which converts a first analog input signal and a second analog input signal to a first digital output signal and a second digital output signal respectively, the multiple input AD conversion apparatus comprises:

• a first sample-and-hold circuit to sample and hold a first analog input signal;
• a second sample-and-hold circuit to sample and hold a second analog input signal;
• a first unit AD converter following the first sample-and-hold circuit and including a plurality of first conversion stages connected in cascade to convert the first analog input signal to the first digital output signal;
• a second unit AD converter following the second sample-and-hold circuit and including a plurality of second conversion stages connected in cascade to convert the second analog input signal to the second digital output signal;
• and
• a plurality of operational amplifiers each configured to be shared between a corresponding first conversion stage of the first conversion stages and a corresponding second conversion stage of the second conversion stages in a time sharing.