Abstract: Embodiments of an analog-to-digital converter (ADC), resistive digital-to-analog converter (DAC) circuits, and methods of operating an ADC are disclosed. In an embodiment, an analog-to-digital converter includes a DAC unit configured to convert a digital code to a first voltage in response to an input voltage of the ADC, a comparator configured to compare the first voltage with a second voltage to generate a comparison output, and a logic circuit configured to generate the digital code, to control the DAC unit based on the comparison output, and to output the digital code as a digital output of the ADC. The DAC unit includes a capacitive DAC and multiple resistive DACs. Each of the resistive DACs is connected to the first voltage through a respective capacitor.

Abstract: An integrated charge redistribution successive approximate register (CR-SAR) analog-to-digital converter (ADC) includes a sample-and-hold switch, a digital-to-analog converter (DAC), a comparator and a logic circuit. The sample-and-hold switch obtains a sample input voltage (Vin). The DAC includes a plurality of digital multiplexers that selects between a superposition phase, which superimposes an analog offset voltage onto Vin, and a conversion phase which determines values for a digital output register which determines the input values to each control line. Each digital multiplexer presents input values to a control line. The comparator has two inputs coupled to the sample-and-hold switch and to the DAC such that the output of the converter determines a value of each successive bit in the digital output register. The logic circuit is coupled to the comparator and to digital multiplexers and includes the digital output register.

Abstract: A low dropout (LDO) regulator system is provided. The LDO regulator system includes a first amplifier circuit, a second amplifier circuit, and a switch circuit. The first amplifier circuit has a first input coupled to receive a reference voltage and an output. The second amplifier circuit has a first input coupled to the output of the first amplifier and is configured to provide a predetermined voltage at a first output. The switch circuit is coupled between the first output of the second amplifier circuit and a second input of the first amplifier circuit and is configured to cause an open circuit in a first feedback path from the first output of the second amplifier circuit to the second input of the first amplifier circuit based on a control signal.

Abstract: A diffused resistor and method for forming a diffused resistor are provided. The diffused resistor comprises a substrate having a first conductivity type; a first well within the substrate having a second conductivity type; and a second well within the first well having the first conductivity type. The resistor further comprises a first and second contact for coupling the resistor to further circuitry. The first and second contacts are each coupled to both the first well and the second well.