Abstract: A circuit that produces a gate drive voltage for a MOS transistor switch includes an input that receives a supply voltage, a regulated voltage generating circuit that produces a regulated voltage, and a voltage storage element. A first switch connects the voltage storage element to sample one of the supply voltage and the regulated voltage during a first of first and second non-overlapping time intervals. The second switch connects the voltage storage element to increase the sampled voltage by another of the supply voltage and the regulated voltage to the gate drive voltage during the second non-overlapping time interval. A third switch connects the voltage storage element to provide the gate drive voltage to the MOS transistor switch during the second non-overlapping time interval. The regulated voltage generating circuit produces the regulated voltage such that a high level of the gate drive voltage exceeds the supply voltage yet is maintained less than a breakdown voltage of the MOS transistor switch.

Abstract: In a switched-capacitor input sampling structure, a resistor connected in series with the input structure, but after the output of the input switch limits the noise bandwidth of the input structure. The selected placement of the resistor does not appreciably limit the slewing or settling time of downstream circuit elements, resulting in a low noise bandwidth, high speed system.

Abstract: A reference buffer suitable for driving switched-capacitor or resistive load circuits provides a very low output impedance. The reference buffer utilizes an amplifier with a very large and controlled transconductance configured in feedback and compensated by a load capacitance. Cascaded gain stages are used to provide a large, controlled transconductance. In one embodiment, a reference buffer amplifier includes a plurality of voltage gain amplifiers connected in cascade and at least one transconductance amplifier connected to a last-connected of the plurality of voltage gain amplifiers. The amplifier may further include at least one current mirror amplifier connected to the at least one transconductance amplifier. In another embodiment, the reference buffer amplifier includes at least one transconductance amplifier and at least one current mirror amplifier cascade-connected to the at least one transconductance amplifier. The amplifiers can be differential or single-ended.

Abstract: A two-stage switched-capacitor residue amplifier having novel circuitry in the first and second stages provides fast and accurate settling while configured with a large closed-loop gain, and also provides low power consumption while powered from a five volt supply. The invention is particularly well suited for use in a multi-stage, pipe-lined analog-to-digital converter (ADC) that converts multiple bits in the first pipeline stage. Complementary PMOS and NMOS differential pairs are used in the first and/or second stage to increase the current slew capability of the amplifier. Current mirror gain and/or positive feedback is used in the second stage to increase transonductance and bandwidth. Cascode transistors are used in the output of the first and/or second stages and active cascode gain enhancement is used in the first stage to increase dc gain and accuracy.

Abstract: An apparatus and method for providing EOS/ESD protection against an EOS/ESD event across first and second pads of an integrated circuit. In one embodiment, the EOS/ESD protection circuit includes an NMOS device having a drain and source respectively coupled to the first and second pads of the integrated circuit, a capacitor coupled between the drain and gate of the NMOS device and a clamping circuit coupled between the gate and the source of the NMOS device to maintain a voltage at the gate less than or equal to a clamping voltage of the clamping circuit. In embodiments of the present invention, the protection circuit includes an active pull down circuit for reducing the voltage across the gate and source of the NMOS device to zero volts a predetermined period of time after the EOS/ESD event, and the protection circuit further includes a current source for providing bias current to the clamping circuit.

Abstract: A high-gain, low-power transconductance amplifier suitable for use in switched-capacitor circuits provides improved accuracy and high-speed operation. The transconductance amplifier includes an input circuit that receives an input voltage. A current mirror circuit is coupled to the input circuit. At least one active cascode circuit, coupled to the current mirror circuit, receives current from the current mirror circuit and provides an output current. The active cascode circuit provides gain enhancement to the transconductance amplifier by increasing the output impedance of the transconductance amplifier.