A novel RF buffer circuit adapted for use with an
RF switch circuit and method for switching RF signals is described. The
RF switch circuit is fabricated in a
silicon-on-insulator (SOI) technology. The
RF switch includes pairs of switching and
shunting transistor groupings used to alternatively couple RF input signals to a common RF node. The switching and
shunting transistor grouping pairs are controlled by a switching control
voltage (SW) and its inverse (SW_). The switching and
shunting transistor groupings comprise one or more
MOSFET transistors connected together in a “stacked” or serial configuration. The stacking of transistor grouping devices, and associated gate resistors, increase the
breakdown voltage across the series connected switch transistors and operate to improve RF switch compression. A fully integrated RF switch is described including
digital control logic and a
negative voltage generator integrated together with the RF switch elements. In one embodiment, the fully integrated RF switch includes a built-in oscillator, a
charge pump circuit,
CMOS logic circuitry, level-shifting and
voltage divider circuits, and an RF buffer circuit. Several embodiments of the
charge pump,
level shifting,
voltage divider, and RF buffer circuits are described. The inventive RF switch provides improvements in
insertion loss, switch isolation, and switch compression.