Abstract: A reference voltage output by a bandgap voltage reference circuit is formed by summing an amplified voltage that has a positive temperature coefficient with a base-to-emitter voltage that has a negative temperature coefficient. The amplified voltage is formed by amplifying a difference voltage &Dgr;VBE. Variations over temperature of the reference voltage are reduced by increasing the magnitude of the difference voltage &Dgr;VBE. By increasing the magnitude of the difference voltage &Dgr;VBE, a smaller gain can be used to form the amplified voltage. By utilizing a smaller gain, less of the error associated with the difference voltage &Dgr;VBE is present in the amplified voltage.

Abstract: An amplifier includes an output buffer having an input coupled to a gain node which is the common node of the outputs of first and second current mirrors for receiving a signal current and having an output for providing an amplified drive current. The output buffer includes a first transistor of a first type having its base coupled to a gain node of the output buffer and to the base of a first transistor of a second type for receiving the signal current. The emitter of the first transistor of a first type is coupled to the base of a second transistor of a second type. The emitter of the first transistor of the second type is coupled to the base of a second transistor of the first type. The emitter of the second transistor of the first type is coupled to the emitter of the second transistor of the second type and to the output of the buffer.

Abstract: An amplifier has an output buffer having an input coupled to the second outputs of the first and second current mirrors for receiving the biasing current and having an output for providing an amplified drive current. The output buffer includes a first transistor of a first type having its base coupled to the input of the output buffer and to the base of a first transistor of a second type. The emitter of the first transistor of a first type coupled to the base of a second transistor of a second type, and a collector. The emitter of the first transistor of the second type is coupled to the base of a second transistor of the first type. The emitter of the second transistor of the first type is coupled to the emitter of the second transistor of the second type and to the output of the buffer. First and second current mirrors of complementary transistor types provide a reference current and a biasing current in response to a programming current and a feedback current.

Abstract: A voltage controlled amplifier which includes a gain core and a transconductive amplifier. The gain core includes two complimentary differential transistor pairs. The emitters of the four transistors of the two differential pairs are connected to complimentary diode connected transistors. The diode connected transistors balance the parasitic resistances of the dissimilar transistors, thereby, reducing differential gain and distortion.

Abstract: A four quadrant multiplier comprises X and Y input stages for coupling signals to a gain core amplifier for multiplication, wherein each of the input stages and the gain core amplifier further comprises a pair of complementary circuits, based on devices having opposite conductivity properties. The complementary X-input stage is a dual differential amplifier which provides balanced, differential outputs when loaded by the gain core differential amplifiers, due to separate cancellation of the npn and pnp base currents within the loaded X-input stage. Outputs from the cross-connected gain core amplifiers provide a pair of complete, ground referenced product signals having opposite phases. The X-input stage is also suitable for driving other complementary, differential stages such as two quadrant multipliers, voltage controlled amplifiers, and high speed analog multiplexing circuits.

Abstract: A lowpass filter circuit having an electronically controllable cutoff frequency and utilizing a feedback current mirror circuit as a variable impedance element. The filter circuit employs low noise, low distortion output circuitry and includes means for electronically controlling resonance.