Patent ID: 8803602
Filing Date: 2014-08-12
Classification: H03F

Abstract:
1. A biasing circuit for providing bias voltage to a differential circuit configured to process signals at frequencies above a pre-determined frequency within a signal band, the differential circuit having a first signal node and a second signal node, the first signal node and second signal node together forming a differential node, the biasing circuit comprising: a bias source having a DC voltage output, the DC voltage output producing a DC bias voltage and having: a first bias resistor having a first bias resistance, the first bias resistor coupled between the DC voltage output and the first signal node so as to provide the DC bias voltage to the first signal node; and a second bias resistor having a second bias resistance, the second bias resistor coupled between the DC voltage output and the second signal node so as to provide the DC bias voltage to the second signal node, wherein the magnitude of the first output impedance being less than 80 percent of the smaller of the magnitude of the first bias resistance and the magnitude of the second bias resistance, and the magnitude of the second output impedance being at least 20 percent of the larger of the magnitude of the first bias resistance and the magnitude of the second bias resistance, provided that the magnitude of the first output impedance is less than fifty percent of the magnitude of the second output impedance.