This work proposes a dual-residue pipelined-SAR ADC, that generates two residue signals from a single amplifier, which eliminates the need for gain-matching calibration. A capacitive interpolating SAR conversion technique is also proposed for the second stage for power efficiency. A prototype ADC fabricated in a 40nm CMOS occupies an active area of 0.026 mm(2) and achieves an SNDR of 62.1 dB at Nyquist and 67.1 dB SFDR under a 0.9 V supply.