High performance pre-mixer buffer in wireless communications systems

摘要

According to one embodiment, a high performance buffer for use in a communications system includes first and second differential blocks. Each of the first and second differential blocks comprise one or more driving transistors for generating a driving current for a load of the high performance buffer, and a feedback path for adjusting the operation of the one or more driving transistors. The feedback path includes a feedback transistor for receiving a common mode bias voltage, wherein the common mode bias voltage depends at least in part on a threshold voltage of the feedback transistor. The feedback path includes a programmable resistor and capacitor to reduce out of band loop gain and the noise. The high performance buffer is configured to achieve a high linearity, low output impedance, and low noise, and is suitable for use as a pre-mixer buffer in a wireless communications system.

主权项

1. A buffer for use in a communications system, said buffer comprising:
first and second differential blocks; each of said first and second differential blocks including at least one driving transistor for generating a driving current for a load, a gate of said at least one driving transistor receiving a first common mode bias voltage depending at least in part on a threshold voltage of said at least one driving transistor; a first feedback path configured to adjust an operation of said at least one driving transistor of said first differential block and including a first feedback transistor that receives a second common mode bias voltage of said first feedback path depending at least in part on a threshold voltage of said first feedback transistor; and a second feedback path configured to adjust an operation of said at least one driving transistor of said second differential block and including a second feedback transistor that receives a second common mode bias voltage of said second feedback path depending at least in part on a threshold voltage of said second feedback transistor, wherein the first feedback path is separate from the second feedback path, and the first feedback path includes a voltage divider that provides a divided voltage to a capacitor, and the divided voltage stored on the capacitor controls a control transistor that adjusts the operation of the at least one driving transistor of the first differential block.