Analog-to-
digital converter (100), ADC, featuring: an input terminal (102) which is configured to receive an analog input
voltage signal (VIN); a first ADC stage (108) which is coupled to the input terminal (102) and is configured to output a first digital value (D1) corresponding to the analog input
voltage signal (VIN) and a first analog residual
signal (VRES1) corresponding to a difference between the first digital value (D1) and the analog input signal (VIN); a first
inverter-based residual
amplifier (114) configured to receive the first analog residual signal (VRES1), amplify the first analog residual signal (VRES1) and output a first amplified residual signal (VRES1G); a second ADC stage (116) configured to receive the first amplified residual signal (VRES1G) and output a second digital value (D2) corresponding to the first amplified analog residual signal (VRES1G) and output a second analog residual signal (VRES2) corresponding to a difference between the second digital value (D2) and the first amplified analog residual signal (VRES1G); a second
inverter-based residual
amplifier (118) configured to receive the second analog residual signal (VRES2), amplify the second analog residual signal (VRES2) and output a second amplified residual signal (VRES2G); a third ADC stage (120) configured to receive the second amplified residual signal (VRES2G) and output a third digital value (D3) corresponding to the second amplified analog residual signal (VRES2G); and a
control unit (300, 330) coupled to the first ADC stage (108), the second ADC stage (116) and the third ADC stage (120) and configured to combine the first digital value (D1), the second digital value (D2) and the third digital value (D3) into a digital output signal (DOUT) which represents the analog input
voltage signal (VIN); wherein the first ADC stage (108) is configured to sample the analog input voltage signal (VIN) during a first operating phase (10, phi1), to convert the analog input voltage signal (VIN) to the first digital value (D1) during a second operating phase (20, phi2), and to retain the first analog residual signal (VRES1) during a third operating phase (30, phi3); wherein the first residual
amplifier (114) is deactivated during the first operating phase (10, phi1), is reset during the second operating phase (20, phi2), and is configured to amplify the first analog residual signal (VRES1) during the third operating phase (30, phi3); and wherein the second ADC stage (116) is set up to sample the amplified first analog residual signal (VRES1) during the third operating phase (30, phi3) and to convert the analog input voltage signal (VIN) during the first operating phase (10, phi1), and to convert the amplified first analog residual signal (VRES1) during the first operating phase (10, phi1) and the second operating phase into the second digital value (D2).