Abstract: An automatic gain control (AGC) amplifier including a high gain transimpedance amplifier, a resistive feedback network and multiple transconductance stages coupled in the feedback path of the AGC amplifier. The feedback network receives an input signal and is coupled to the output of the high gain amplifier and has multiple intermediate nodes. Each transconductance stage has an input coupled to an intermediate node of the feedback network and an output coupled to the input of the high gain amplifier. Each transconductance stage is independently controllable to position a virtual ground within the feedback network to control closed loop gain. Each transconductance stage may have a bias current input coupled to a bias current control circuit. The control circuit controls each bias current to vary the gain of the AGC amplifier. The bias currents may be linearly controlled employing a ramp function to achieve a linear in dB gain response.

Abstract: An electrostatic discharge (ESD) switch circuit for an integrated circuit (IC) with multiple power inputs for improving pin-to-power isolation of the IC. The IC includes a plurality of positive power pins and a corresponding plurality of negative power pins. The IC also includes an ESD ring network with a high ESD bus and a low ESD bus. The IC further includes a control circuit indicating one of several operational modes. The ESD switch circuit includes a first switch circuit that couples the high ESD bus to a first positive power pin in a first operational mode and that couples the high ESD bus to a second positive power pin in a second operational mode. The ESD switch circuit further includes a second switch circuit that couples the low ESD bus to a first negative power pin in the first operational mode and that couples the low ESD bus to a second negative power pin in the second operational mode.