Abstract: Transimpedance amplifier circuits and methods are provided in which the break frequency of the amplifier is adjusted through a single interface point to the amplifier circuit. At frequencies below the break frequency, the amplifier circuit provides an error current which effectively nulls the output of the transimpedance amplifier so that no output is produced. At frequencies above the break frequency, the break frequency setting element is essentially a short circuit that results in the frequency dependent voltage being substantially zero. This causes the transimpedance amplifier to convert current-to-voltage without signal degradation. The circuit also enables a user to adjust the break frequency without affecting the overall operation of the amplifier. Thus, the amplifier may be coupled to different output circuits for operations in accordance with different communication standards.

Abstract: An integrated high gain amplifier in which voltage at the high impedance output node is sensed by sensing voltage excursions which are proportional to the output voltage at another point in the circuit which is coupled to the output node to boost the gain of the amplifier.

Abstract: An operational amplifier having input and output stages with positive capacitive feedback to the output stage derived from a point in the circuit where the voltage is proportional to the output voltage.