Impedance balancing for power supply rejection in single-ended receivers

摘要

Power supply rejection in a single-ended receiver, through impedance balancing, is described. The single-ended receiver includes a first low noise amplifier and a second low noise amplifier. The single-ended receiver also includes a multi-port coupled transformer that outputs a differential signal. The multi-port coupled transformer includes a first primary coil that is coupled to an output of the first low noise amplifier and a second primary coil. The single-ended receiver also includes balancing impedances at the output of each of the low noise amplifiers. These impedances can be configured such that the on impedance of the first low noise amplifier equals the combined impedance of the off impedance of the second low noise amplifier and the balancing impedance. This balancing of impedances on the first and second primary coils results in power supply rejection of noise and spurious signals.

主权项

1. A single-ended receiver for power supply rejection, comprising:
a first low noise amplifier; a second low noise amplifier; a first balancing impedance coupled to the output of the first low noise amplifier via a first switch and to ground; a second balancing impedance coupled to the output of the second low noise amplifier via a second switch and to ground; and a multi-port coupled transformer that outputs a differential signal, the multi-port coupled transformer comprising:
a first primary coil that is coupled to an output of the first low noise amplifier; anda second primary coil, wherein the first primary coil and the second primary coil are tightly coupled as a differential inductor.