Variable level power clamping circuit

A radio-frequency receiver having a low-noise amplifier and including:

• (a) an output selection switch having a first input, a second input, and an output;
• (b) a low-noise amplifier coupled to the first input of the output selection switch;
• (c) an amplification path coupled to the low-noise amplifier;
• (d) an inductor series coupled to the amplification path at an internal node on the amplification path between the inductor and the low-noise amplifier;
• (e) a bypass path coupled to the second input of the output selection switch;
• (f) a multipath switch, coupled to the inductor and to the bypass path and configured to be coupled to one or more radio frequency (RF) signal lines, for selectively coupling one of the RF signal lines to the inductor or to the bypass path;
• (g) a switch coupled to the internal node;
• (h) a capacitor coupled to the switch and to the bypass path;
• and
• (i) a power clamping circuit coupled to the internal node;
• wherein when the switch is open, the power clamping circuit limits power on the amplification path to the low-noise amplifier, and
• wherein when the switch is closed, (1) signals on an RF signal line selected by the multipath switch are coupled through the inductor, the amplification path, the switch, and the capacitor to the bypass path;
• (2) the inductor and the capacitor comprise an impedance transform circuit wherein the impedance transform circuit transforms the impedance of the amplification path to a first impedance at the internal node, and the capacitor transforms the first impedance at the internal node to a second impedance on the bypass path after the impedance transform circuit;
• and (3) the power clamping circuit limits power at the internal node and operates at a voltage higher than the voltage of the amplification path or the bypass path as a result of the action of the impedance transform circuit.