Abstract: An amplitude-stabilized second-order predistortion circuit includes a main cell having a differential input for receiving a differential input voltage, a differential output for providing a differential output voltage, and a load control input for receiving a load control voltage; a replica cell having a differential input for receiving a differential level of peak input voltage, a differential peak output voltage, and a load control input; and a control circuit coupled to the differential output of the replica cell and driving the load control inputs of the main cell and the replica cell. The main cell and the replica cell are multiplier cells each having a variable load. The control circuit includes a first amplifier for generating a single-ended peak signal and a second amplifier for generating the load control voltage from the difference between the replica cell single-ended peak output signal and a single-ended peak reference signal.

Abstract: A capacitance compensation circuit includes an input terminal, a plurality of switches coupled to the input terminal, a plurality of varactors coupled to the plurality of switches, and a plurality of blocking capacitors coupled between the plurality of switches and the plurality of varactors. The capacitance compensation circuit further includes a plurality of adjustable biasing circuits to precisely compensate for linear and parabolic voltage dependent components of an input or other capacitor. Two such circuits can be used with a single input terminal to compensate for both increasing and decreasing voltage dependent characteristics of a target capacitor.

Abstract: A capacitance compensation circuit includes a plurality of switches having a first node coupled to an input terminal, a plurality of capacitors each coupled to a respective second node of the plurality of switches, and an adjustment circuit for providing a plurality of adjustable bias levels to a plurality of switch control nodes to precisely compensate for linear and parabolic voltage dependent components of an input or other capacitor. Two such circuits can be used with a single input terminal to compensate for both increasing and decreasing voltage dependent characteristics of a target capacitor.

Abstract: A radiation-hardened reference circuit includes a precision voltage reference circuit for generating a current-controlling voltage at first and second terminals, a driver circuit for receiving the current-controlling voltage at first and second terminals and for generating an output reference voltage, and a differential sampling circuit having first and second input terminals coupled to the first and second terminals of the voltage reference circuit, and first and second output terminals coupled to the first and second terminals of the driver circuit.

Abstract: Circuits and methods that improve the performance of voltage reference driver circuits and associated analog to digital converters are provided. A voltage reference driver circuit that maintains a substantially constant output voltage when a load current is modulated by an input signal is provided. The voltage reference driver circuit synchronously decouples a voltage regulation circuit from the load circuit when modulating events such as pulses caused by the load circuit during a switching interval are generated, preventing disturbance of the regulation circuitry and keeping its output voltage substantially constant.

Abstract: Circuits and methods that improve the performance of voltage reference driver circuits and associated analog to digital converters are provided. A voltage reference driver circuit that maintains a substantially constant output voltage when a load current is modulated by an input signal is provided. The voltage reference driver circuit synchronously decouples a voltage regulation circuit from the load circuit when modulating events such as pulses caused by the load circuit during a switching interval are generated, preventing disturbance of the regulation circuitry and keeping its output voltage substantially constant.

Abstract: Circuits and methods that improve the performance of electronic sampling systems are provided. Parasitic capacitance associated with bootstrap circuitry is reduced, thereby decreasing signal distortion caused by capacitive loading at the input of the sampling circuit. The impedance of a sampling semiconductor switch is maintained substantially constant during sample states, at least in part, by accounting for non-linear parasitic capacitances associated with a sampling switch control terminal in order to reduce or minimize signal distortion associated with sampled signals that pass through the sampling switch.

Abstract: A method digitally representing an integral non-linearity response for a device includes: (a) In no particular order: (1) Identifying locations of significant departures of the integral response, including: [a] Extracting first and second differential responses from the integral response in first and second device trim states. [b] Twice-filtering first and second differential responses to produce first and second filtered responses. [c] Determining difference between first and second filtered responses to produce a treated response. [d] Identifying a locus for each maximum of the treated response in a highest excursion range and in at least one lower excursion range. [e] Imposing zero amplitude on the treated response within a code range of each locus. Locations are centered within each code range. (2) Determining magnitude for each significant departure.

Abstract: A method for determining a minimization factor for improving linearity of an analog-to-digital converter including a plurality of components includes the steps of: (a) Evaluating integral non-linearity response of the apparatus to identify significant departures of the response greater than a predetermined amplitude and to relate each respective significant departure with a respective identified component. (b) Determining magnitude of each significant departure. (c) Identifying a trimming factor related with each component. (d) Determining a residual gap magnitude for each significant departure. The residual gap magnitude comprises the magnitude of the respective significant departure less the trimming factor related with the identified component. (e) Determining the minimization factor as a sum of the residual gap magnitudes for a selected plurality of the identified components.

Abstract: A clock signal preamplifier comprises complementary pairs of differentially coupled transistors, with an output signal coupled to an inverter further comprising a totem-pole arrangement of complementary MOSFET transistors. The input signal to the preamplifier is typically sinusoidal, and the output signal is rectangular. Preferably, the differentially coupled transistors are bipolar, and a pair of diode clamper circuits with bipolar transistors is preferably coupled to the complementary pairs of differentially coupled transistors. A reference voltage source is coupled to the control terminals of the clamper transistors. A reference voltage source, which preferably comprises a totem-pole arrangement of complementary MOSFET transistors with its output node is coupled to its input node, provides a reference voltage for the diode clamper circuits.

Abstract: A reference voltage circuit having an open-loop buffer driven by a matching buffer included within a closed-loop, generates a stable differential or single-ended voltage while minimizing signal-dependent short-term and long-term drift. The open-loop buffer may be a replica of the closed-loop buffer, reducing the effect of a signal coupled on the voltage reference lines. The reference voltage circuit may be adapted for a switched capacitor ADC.

Abstract: A method for determining a minimization factor for improving linearity of an analog-to-digital converter including a plurality of components includes the steps of: (a) Evaluating integral non-linearity response of the apparatus to identify significant departures of the response greater than a predetermined amplitude and to relate each respective significant departure with a respective identified component. (b) Determining magnitude of each significant departure. (c) Identifying a trimming factor related with each component. (d) Determining a residual gap magnitude for each significant departure. The residual gap magnitude comprises the magnitude of the respective significant departure less the trimming factor related with the identified component. (e) Determining the minimization factor as a sum of the residual gap magnitudes for a selected plurality of the identified components.

Abstract: An apparatus switching an input signal by a switching transistor in response to a clock includes: (a) A capacitor. (b) A charging circuit coupled for charging the capacitor with a supply voltage in response to the clock. (c) A switching circuit coupled with the capacitor and configured for coupling the switching transistor with the capacitor in response to the clock. (d) A grounding circuit coupled with the switching transistor and a ground locus. The grounding circuit includes a first grounding transistor coupled with the switching transistor and a second grounding transistor. The first grounding transistor has connection loci permitting electrical coupling with the gate, the source, the drain and the bulk portion of the first grounding transistor. The source connection locus and the bulk connection locus are coupled in common. The second grounding transistor couples the first grounding transistor with the ground locus in response to the clock.

Abstract: A method digitally representing an integral non-linearity response for a device includes: (a) In no particular order: (1) Identifying locations of significant departures of the integral response, including: [a]Extracting first and second differential responses from the integral response in first and second device trim states. [b] Twice-filtering first and second differential responses to produce first and second filtered responses. [c] Determining difference between first and second filtered responses to produce a treated response. [d] Identifying a locus for each maximum of the treated response in a highest excursion range and in at least one lower excursion range. [e] Imposing zero amplitude on the treated response within a code range of each locus. Locations are centered within each code range. (2) Determining magnitude for each significant departure.

Abstract: A reference voltage circuit having an open-loop buffer driven by a matching buffer included within a closed-loop, generates a stable differential or single-ended voltage while minimizing signal-dependent short-term and long-term drift. The open-loop buffer may be a replica of the closed-loop buffer, reducing the effect of a signal coupled on the voltage reference lines. The reference voltage circuit may be adapted for a switched capacitor ADC.

Abstract: A clock signal preamplifier comprises complementary pairs of differentially coupled transistors, with an output signal coupled to an inverter further comprising a totem-pole arrangement of complementary MOSFET transistors. The input signal to the preamplifier is typically sinusoidal, and the output signal is rectangular. Preferably, the differentially coupled transistors are bipolar, and a pair of diode damper circuits with bipolar transistors is preferably coupled to the complementary pairs of differentially coupled transistors. A reference voltage source is coupled to the control terminals of the damper transistors. A reference voltage source, which preferably comprises a totem-pole arrangement of complementary MOSFET transistors with its output node is coupled to its input node, provides a reference voltage for the diode damper circuits.

Abstract: The number of compensation capacitors of an opamp may be reduced by connecting the compensation/decoupling capacitor element or elements between the load node and the bias node of the operational amplifier, rather than providing separate capacitive elements from each load node to ground (the reference voltage). This allows one to both reduce the overall area occupancy of the operational amplifier, and/or to improve the settling characteristics of its common-mode and differential output signal. The opamp may be part of a multi-stage amplifier or an analog-to-digital converter (ADC) (e.g., a pipelined ADC), which may form part of a multi-stage wireless communications base station receiver.

Abstract: The number of compensation capacitors of an opamp may be reduced by connecting the compensation/decoupling capacitor element or elements between the load node and the bias node of the operational amplifier, rather than providing separate capacitive elements from each load node to ground (the reference voltage). This allows one to both reduce the overall area occupancy of the operational amplifier, and/or to improve the settling characteristics of its common-mode and differential output signal. The opamp may be part of a multi-stage amplifier or an analog-to-digital converter (ADC) (e.g., a pipelined ADC), which may form part of a multi-stage wireless communications base station receiver.

Abstract: A two-phase non-overlapping clock generator (12) generating a sampling signal (20) utilizing a three transistor NAND gate (50). The NAND gate of the present invention eliminates one large PMOSFET (46), and has one NMOSFET (52) driven by the other phase and having its source grounded. The present invention yields substantial improvement on the jitter of the clock phases. Both rising and falling transitions are improved because of the greatly reduced self-loading of the NAND gate. Overshooting is eliminated, and the NAND gate body effect is minimized, providing enhanced jitter performance of the sampling signal and improving a signal to noise ratio (SNR). The principle of the present invention are also embodied in a NOR gate (70).

Abstract: A two-phase non-overlapping clock generator (12) generating a sampling signal (20) utilizing a three transistor NAND gate (50). The NAND gate of the present invention eliminates one large PMOSFET (46), and has one NMOSFET (52) driven by the other phase and having its source grounded. The present invention yields substantial improvement on the jitter of the clock phases. Both rising and falling transitions are improved because of the greatly reduced self-loading of the NAND gate. Overshooting is eliminated, and the NAND gate body effect is minimized, providing enhanced jitter performance of the sampling signal and improving a signal to noise ratio (SNR). The principle of the present invention are also embodied in a NOR gate (70).