Noise shaping in multi-stage analog-to-digital converters

An analog-to-digital converter (ADC) comprising:

• a first conversion stage having a residue output;
• an amplifier having an input selectively coupled to the residue output of the first conversion stage;
• a second conversion stage having an input selectively coupled to an output of the amplifier;
• and
• a switched-capacitor network having a first port coupled to the input of the amplifier and having a second port coupled to the input of the second conversion stage, the switched-capacitor network having a first capacitive element having a first terminal coupled to the second port and having a second terminal selectively coupled to a reference potential node of the ADC and selectively coupled to the first port.

An analog-to-digital converter (ADC) comprising:

• first means for converting an analog input signal to a first digital output signal;
• means for amplifying a residue from the first means for converting;
• second means for converting the amplified residue to a second digital output signal;
• and
• means for providing a second-order or higher noise transfer function for noise shaping of quantization noise of the second means for converting.