Tunable radio frequency low noise amplifier

1. An apparatus comprising:

an amplifier comprising:

an amplifier input;

a capacitor having a capacitor first side and a capacitor second side, wherein the capacitor first side is coupled to the amplifier input;

a switch having a switch first side and a switch second side, wherein the switch first side is coupled to the capacitor second side;

a transistor having a transistor gate, a transistor source, and a transistor drain, wherein the transistor gate is coupled to the amplifier input and the capacitor first side, wherein the transistor source is coupled to the switch second side and wherein the switch is positioned directly between the capacitor second side and the transistor source;

an inductor having an inductor first end and an inductor second end, wherein the inductor first end is coupled to the switch second side and the transistor source, and wherein the inductor second end is coupled to a ground;

a second capacitor having a second capacitor first side and a second capacitor second side, wherein the second capacitor first side is coupled to the amplifier input, and a second switch having a second switch first side and a second switch second side, wherein the second switch first side is coupled to the second capacitor second side, and wherein the second switch second side is coupled to the first switch second side, the inductor first end, and the transistor source; and

a third capacitor having a third capacitor first side and a third capacitor second side, wherein the third capacitor first side is coupled to the amplifier input, and wherein the third capacitor second side is directly connected to the switch second side, the second switch second side, the inductor first side, and the transistor source without any intervening components.

2. The apparatus of claim 1 , wherein the amplifier input is directly connected to the capacitor first side and the transistor gate without any intervening components.

3. The apparatus of claim 1 , wherein the amplifier further comprises a controller coupled to the first switch and the second switch, and wherein the controller is configured to vary an operating frequency range of the amplifier by opening and closing the first switch and the second switch.

4. The apparatus of claim 1 , wherein the amplifier further comprises an amplifier output and a second transistor, wherein the second transistor has a second transistor gate, a second transistor source, and a second transistor drain, wherein the second transistor gate is coupled to a bias voltage potential, wherein the second transistor source is coupled to the transistor drain, and wherein the second transistor drain is coupled to the amplifier output.

5. The apparatus of claim 4 , wherein the amplifier further comprises a load having a load first end coupled to a voltage potential and a load second end coupled to the second transistor drain and the amplifier output.

6. The apparatus of claim 5 , further comprising an antenna, a surface acoustic wave (SAW) filter or a duplexor coupled to the antenna, a matching network coupled to the SAW filter or the duplexor, a mixer coupled to the matching network, and a baseband filter coupled to the mixer, wherein the amplifier is positioned between the matching network and the mixer.

7. The apparatus of claim 6 , wherein the apparatus has only one amplifier for a plurality of input electrical signal frequency bands, and wherein the apparatus has only one amplifier positioned between the matching network and the mixer.

8. The apparatus of claim 6 , wherein the apparatus is a communications device.