Adc with noise-shaping sar and digitization of quantization error

An analog-to-digital converter device, comprising:

• a first stage having a first input that receives a first analog signal, a second input that receives a second analog signal, and an output that transmits a first digital output signal based on the first analog signal and the second analog signal, the first stage includes a successive approximation register that performs successive approximations of the first analog signal and the second analog signal to provide the first digital output signal, the successive approximation register includes a passive switched-capacitor integrator that integrates a first residual signal that is based on the successive approximations of the first analog signal and a second residual signal that is based on the successive approximations of the second analog signal to provide a first stage quantization error,
• wherein the passive switched-capacitor integrator includes a first sampling capacitor configured to sample the first residual signal during a first set of signals and provide a first sample of the first residual signal to a first integrator capacitor during a second set of signals that is different than the first set of signals and alternates with the first set of signals, a second sampling capacitor configured to sample the first residual signal during the second set of signals and provide a second sample of the first residual signal to the first integrator capacitor during the first set of signals, a third sampling capacitor configured to sample the second residual signal during the first set of signals and provide a first sample of the second residual signal to a second integrator capacitor during the second set of signals, and a fourth sampling capacitor configured to sample the second residual signal during the second set of signals and provide a second sample of the second residual signal to the second integrator capacitor during the first set of signals.

A method of converting an analog signal to a digital signal in an analog-to-digital converter device, the method comprising:

• receiving a first analog signal at a first input of a successive approximation register;
• receiving a second analog signal at a second input of the successive approximation register;
• performing, by the successive approximation register, successive approximations of the first analog signal and the second analog signal;
• generating, by the successive approximation register, a first digital output signal based on the successive approximations of the first analog signal and the second analog signal;
• integrating, by a passive switched-capacitor integrator, a first residual signal that is based on the successive approximations of the first analog signal;
• integrating, by the passive switched-capacitor integrator, a second residual signal that is based on the successive approximations of the second analog signal;
• and
• generating a filtered first stage quantization error based on the integrating of the first residual signal and the second residual signal.