High-Voltage CMOS RF Switch with Active Biasing

In this paper a stacked MOSFET (metal-oxide-semiconductor field effect transistor)-based RF (radio-frequency) switch comprising an active biasing circuit is demonstrated. The active biasing circuit regulates the DC voltage at the source-drain nodes of the stack, thus compensating for the self-biasing effect when the switch is exposed to a high-power RF signal. Such operating point regulation improves the robustness of the OFF-state switch against the applied RF voltage. Two high-voltage RF switches – a reference one with the passive resistive bias network and the proposed one comprising the active biasing – have been designed and implemented in a dedicated 130 nm bulk-CMOS (Complementary Metal-Oxide-Semiconductor) RF switch technology. The device with the active biasing circuit has demonstrated 6 V higher RF breakdown voltage comparing to the reference switch (62 V versus 56 V respectively). All other relevant RF parameters of the switch remain unchanged.