Abstract: Described herein are differentiated transistor isolation techniques. In one example, an integrated circuit structure may include transistors, where spacer structures or insulator regions that separate adjacent transistors from one another include one or more different materials. For example, an integrated circuit structure may include a first insulator region between first and second transistors, where the first insulator region includes a first insulator material (e.g., in the same layers as the channel regions of the transistors) and a second insulator material over the first insulator material. The IC structure may include a second insulator region between third and fourth transistors, where the second insulator region includes the second insulator material (e.g., in the same layers as the channel regions of the transistors).

Abstract: A sigma-delta digital-to-analog converter comprises a current digital-to-analog converter (IDAC) stage which generates a current depending on an input digital signal. An output current-to-voltage converter converts the generated signal to a voltage on a continuous-time basis. The amplifier used in the output current-to-voltage converter is chopper-stabilized. The converter can be single bit or multi-bit. The IDAC stage can be implemented with a pair of branches, a first branch comprising a first biasing current source and a second branch comprising a second biasing current source. The biasing current sources can be chopper-stabilized by connecting the bias current sources to the output current-to-voltage converter by a set of switches. The switches connect the biasing current sources to the output current-to-voltage converter in a first configuration and a second, reversed, configuration. This modulates flicker noise contributed by the bias current sources to the chopping frequency.

Abstract: A multi-bit continuous-time sigma-delta analog-to-digital converter (ADC) has a differential input stage which receives an analog input signal current. A multi-bit feedback current digital-to-analog converter (IDAC) generates a multi-level feedback current depending on a digital feedback signal from a flash ADC. An integrator has a differential input that integrates the difference of the generated current by the multi-bit IDAC and the input signal current on a continuous-time basis. The input stage further comprises a first biasing current source and a second biasing current source which bias the input stage in a mid-scale condition. A first summing node connects to the first differential input line, a first differential input of the integrator and the first output branch. A second summing node connects to the second differential input line, a second differential input of the integrator and the second output branch.

Abstract: A multi-bit sigma-delta analog-to-digital converter (ADC) has a single-ended input for receiving an analog input signal. A multi-bit feedback current digital-to-analog converter (IDAC) generates a multi-level feedback current depending on a multibit digital feedback signal from a Flash ADC. The feedback current is summed with the input signal with the feedback current. The summed signal is integrated on a continuous-time basis. The IDAC is selectively connectable to the summing node via a first path and a second path. The first path transmits current from the IDAC to the summing node with a first polarity and the second path transmits current from the IDAC to the summing node with an inverted polarity. This can reduce flicker noise and can allow the converter to operate without any mid-scale biasing current sources.