Pipeline analog-to-digital converter stages with improved transfer function

A pipeline analog-to-digital converter comprising:

• a plurality of calibrated stages, each of the plurality of calibrated stages comprising:
• an amplifier generating an output representing an amplified difference between a first voltage at an input of the amplifier and a second voltage at another input of the amplifier, and
• a dither capacitor having a first terminal coupled to the input of the amplifier and a second terminal selectively coupled to:
• either a first reference voltage or a second reference voltage lower than the first reference voltage depending on a bit value in a sequence of binary values responsive to a voltage received by the calibrated stage being within a first range, and
• the first reference voltage independent of the sequence of binary values responsive to the received voltage being within a second range;
• and
• a correction circuit coupled to the plurality of calibrated stages and configured to adjust a calibration coefficient that accounts for a gain error of a calibrated stage.

A method comprising:

• receiving a voltage by a calibrated stage of a pipeline analog-to-digital converter, the calibrated stage including an amplifier and a dither capacitor, the amplifier generating an output representing an amplified difference between a first voltage at an input of the amplifier and a second voltage at another input of the amplifier, the dither capacitor having a first terminal coupled to the input of the amplifier;
• and
• selectively coupling a second terminal of the dither capacitor to:
• either a first reference voltage or a second reference voltage lower than the first reference voltage depending on a bit value in a sequence of binary values responsive to a voltage received by the calibrated stage being within a first range,
• the first reference voltage independent of the sequence of binary values responsive to the received voltage being within a second range, and
• the second reference voltage responsive to the received voltage being within a third range different from the first range and the second range, the first range is higher than the second range and the third range is higher than the second range.