A calibration method of a pipeline analog-to-
digital converter (ADC) that includes a
residue amplifier includes the following steps: (A) generating an offset
voltage; (B) adjusting a first input
voltage of the
residue amplifier according to the offset
voltage and a reference digital code; (C) converting an output voltage of the
residue amplifier into a second digital code; (D) performing a correlation operation on the reference digital code and the second digital code to generate an intermediate
gain; (E) recording the intermediate
gain; (F) repeating step (A) to step (E) to
record a plurality of intermediate gains; (G) selecting one of the intermediate gains as a digital
gain according to the second digital code; and (H) generating an output digital code according to a first digital code, the reference digital code, the digital gain, and the second digital code.