Abstract: A method and circuit for eliminating input voltage offset in an amplifier circuit are provided. An exemplary offset correction circuit is configured with DC restoration to eliminate the DC input voltage offset by suitably providing a correction voltage to correct an input voltage offset during operation of the amplifier circuit, without realizing recovery time problems associated with AC coupling. An exemplary offset correction circuit is configured with DC restoration and comprises a timing circuit, a sample and hold circuit, and a feedback circuit to provide a correction voltage signal to correct input voltage offset. The timing circuit is configured to determine a “dead time” and “live time” for operation of the amplifier circuit. During the “dead time” period the sample and hold circuit will sample a differential signal across the DC coupling and provide a feedback signal through feedback circuit to correct input offset voltage.

Abstract: A method and circuit for facilitating control of the AC coupling for addressing input offset in an amplifier circuit are provided. In accordance with an exemplary embodiment, a control circuit comprises a pair of resistive networks coupled together through a capacitive coupling, with the pair of resistive networks configured between two amplifier devices of the amplifier circuit. The capacitive coupling is configured to prevent offset in the differences between input voltages to the two amplifier devices, and can comprise various types and configurations of capacitor networks, devices and components. The pair of resistive networks is configured to generate an output current signal from the two amplifier devices while facilitating a substantially identical capacitive loading on the two amplifier devices.

Abstract: A programmable gain low noise amplifier includes a tail current transistor (Q3) having a source coupled to a first reference voltage (VDD) and a drain coupled to a tail current conductor (18) and, in a differential input embodiment, a plurality of pairs (Q4,5, Q7,8, Q10,11, Q13,14) of differentially coupled input transistors. Each pair includes a first input transistor having a gate coupled to a first input conductor (19A) and a drain coupled to a first output conductor (26A) and a second input transistor having a gate coupled to a second input conductor (19B), a source coupled to a source of the first transistor, and a drain coupled to a second output conductor (26B). The sources of the first and second input transistors of some or all of the pairs are selectively coupled to the tail current conductor (18) in it response to corresponding gain control signals (B1,2,3).