Abstract: A data converter and an impedance matching control method are provided. The data converter includes a comparator, a capacitor array as well as a switch and impedance matching circuit. The comparator includes a first input terminal and a second input terminal. The capacitor array includes a plurality of capacitors, and a first end of each capacitor is coupled to the first input terminal or the second input terminal. The switch and impedance matching circuit is coupled to a second end of a target capacitor among the capacitors and configured to couple the second end to a first reference voltage or a second reference voltage according to a control signal and adjust an impedance according to an impedance adjusting signal, in which the impedance is the impedance of the switch and impedance matching circuit. The first reference voltage is different from the second reference voltage.

Abstract: Disclosed is a correcting device of successive approximation analog-to-digital conversion. The correcting device includes a successive approximation register analog-to-digital converter (SAR ADC) and a digital circuit. The SAR ADC is configured to generate a digital output. The digital circuit is configured to determine whether the digital output conforms to a metastable output, and correct the digital output when the digital output conforms to the metastable output. The metastable output is related with a metastable binary comparison-results sequence including successive K comparison results such as 110000 or 001111. The K comparison results include a first comparison result, a second comparison result and successive M comparison results in turn. The first comparison result and the second comparison result are the same; the M comparison results are the same; each of the first comparison result and the second comparison result is different from any of the M comparison results.

Abstract: A sigma delta modulator includes an integrator, a quantizer, a randomization circuit, and a digital to analog converter circuit. The integrator is configured to integrate an analog signal, in order to generate a first signal, in which the analog signal is a sum of an input signal and a second signal. The quantizer is coupled to the integrator and configured to quantize the first signal to generate a digital signal which has a plurality of bits. The randomization circuit is coupled to the quantizer, and is configured to randomize partial bits in the plurality of bits of the digital signal, in order to generate first control signals. The digital to analog converter (DAC) circuit is coupled to the quantizer and the randomization circuit, and is configured to generate the second signal according to the first control signals and remaining bits in the plurality of bits of the digital signal.

Abstract: A reference voltage buffer circuit includes an operational amplifier, a capacitor switching module, a first transistor and a second transistor. The operational amplifier includes two input terminals and an output terminal, where the two input terminals receive an input reference voltage and a feedback voltage, respectively. A gate electrode of the first transistor is coupled to the capacitor switching module, and a source electrode of the first transistor provides the feedback voltage. A gate electrode of the second transistor is coupled to the capacitor switching module, and a source electrode of the second transistor provides an output reference voltage. In addition, the operational amplifier generates a stable control voltage to the gate electrodes of the first transistor and the second transistors via the capacitor switching module while the output terminal of the operational amplifier is not directly connect to the gate electrodes of the first transistor and the second transistors.