A successive approximation register (SAR) analog-to-digital converter (ADC) includes a ring oscillator configured to determine a frequency based on a sampling clock signal and a first control code, and generate an output clock signal having the determined frequency. The SAR ADC further includes a controller configured to generate the first control code based on a count value indicating a number of times of toggling the output clock signal.

A digital down converter with equalization includes a composite ADC that performs demodulation of a received analog signal, converting the signal into in phase baseband signal and quadrature baseband signal. Equalization is performed to correct for misalignment of the frequency responses of the sub-ADCs in the composite ADC. In a form, ADC output signals are applied to a mixer array to frequency down-shift the digital form of the input signal, followed by digital filtering to effect convolutions of portions of the digital form of the input signal with a set of convolution coefficients determined so that the net processing is mathematically equivalent to down conversion with equalization. In another form, the ADC output signals are directly applied to a digital filter to effect both frequency down-shifting and convolutions, with filter coefficients determined so that the net processing is mathematically equivalent to down conversion with equalization.

An A/D converter has an analog input terminal, an analog output terminal, a digital output terminal, a first resistance comprising one end connected to the analog input terminal or a reference voltage line and another end connected to a first node, a second resistance comprising one end connected to the first node and another end connected to the analog output terminal, an operational amplifier comprising a first input terminal connected to the first node, a second input terminal connected to the reference voltage line or the analog input terminal, and an output terminal connected to the analog output terminal, a quantizer comprising an input terminal connected to the analog input terminal and an output terminal connected to the digital output terminal, and a DA converter comprising an input terminal connected to the digital output terminal and an output terminal connected to the first node.

Systems and methods are provided for a successive approximation register (SAR) analog-to-digital converter (ADC) with an ultra-low burst error rate. Analog-to-digital conversions may be applied via a plurality of successive conversion cycles, with each conversion cycle corresponding to a particular bit in a corresponding digital output. Meta-stability may be detected during each one of the plurality of successive conversion cycles, and for each one of the plurality of successive conversion cycles, a next one of the plurality of successive conversion cycles may be triggered based on a cycle termination event. After completion of all of the plurality of successive conversion cycles, a meta-stability state of each of the plurality of successive conversion cycles may be assessed, and the digital output may be controlled based on the assessment.

A successive approximation register (SAR) analog-to-digital converter (ADC) includes a ring oscillator configured to determine a frequency based on a sampling clock signal and a first control code, and generate an output clock signal having the determined frequency. The SAR ADC further includes a controller configured to generate the first control code based on a count value indicating a number of times of toggling the output clock signal.

An A/D converter has an analog input terminal, an analog output terminal, a digital output terminal, a first resistance comprising one end connected to the analog input terminal or a reference voltage line and another end connected to a first node, a second resistance comprising one end connected to the first node and another end connected to the analog output terminal, an operational amplifier comprising a first input terminal connected to the first node, a second input terminal connected to the reference voltage line or the analog input terminal, and an output terminal connected to the analog output terminal, a quantizer comprising an input terminal connected to the analog input terminal and an output terminal connected to the digital output terminal, and a DA converter comprising an input terminal connected to the digital output terminal and an output terminal connected to the first node.

A CT-SDADC of the present disclosure converts the analog input signal from a representation in an analog signal domain to a representation in a digital signal domain to provide the digital output signal. The CT-SDADC achieves the analog-to-digital conversion and ELDC by switching between two phases in the SAR sub-ADC: a sampling phase and a conversion phase. During the sampling phase, the SAR sub-ADC captures the analog input signal across multiple arrays of switchable capacitors. The conversion phase comprises a number of steps, and one or more bits of the digital output signal are resolved at each step of the conversion phase. A portion of the SC-DAC is driven by the delayed CT-SDADC output during the conversion phase to effectively compensate for excess loop delay caused by the CT-SDADC feedback loop.

Examples are disclosed related to analog to digital conversions. One example provides a conversion circuit comprising a first analog-to-digital converter (ADC) configured to convert an analog voltage to generate a first subset of digital output bits from a most significant bit (MSB) to a bit k and a second subset of digital output bits from a bit k1 to a least significant bit (LSB) of the first ADC. The bit k is between the MSB and the LSB. The first ADC comprises a residual output configured to output a residual voltage of the analog voltage after converting the bit k. The conversion circuit further comprises an amplifier stage connected to the residual output and configured to generate an amplified residual voltage. The conversion circuit further comprises a second ADC connected to the amplifier stage and configured to convert the amplified residual voltage to generate extra digital output bits.