Transceiver and integrated circuit

1. An integrated circuit, comprising:

a balun, having an outer boundary, comprising:

a primary winding, adapted to receive an input signal; and

a secondary winding, magnetically coupled to the primary winding, adapted to convert the input signal into a differential form;

a transistor pair, connected to the secondary winding, adapted to amplify the input signal; and

a source degeneration inductor comprising a degeneration inductor winding, connected to the transistor pair, located within the outer boundary of the balun, wherein the degeneration inductor winding is formed such that a mutual inductance between the degeneration inductor winding and the secondary winding, whereby current flowing in the secondary winding has a direction the same as current flowing in the degeneration inductor winding.

2. The integrated circuit of claim 1 , wherein the balun further has an inner boundary, and the degeneration inductor winding is further encompassed by the inner boundary of the balun.

3. The integrated circuit of claim 1 , wherein each of the secondary winding and the degeneration inductor winding has one turn in parallel to each other, and the parallel turns of the secondary winding and the degeneration inductor winding have a spacing therebetween.

4. The integrated circuit of claim 3 , wherein the spacing is determined according to a magnetic coupling factor k between the secondary winding and the degeneration inductor winding.

5. The integrated circuit of claim 3 , wherein the spacing is in a range of 5 to 10 micro meters.

6. The integrated circuit of claim 3 , wherein the spacing is arranged to increase a magnetic coupling effect between the secondary winding and the degeneration inductor winding.

7. The integrated circuit of claim 3 , wherein the parallel turns of the secondary winding and the degeneration inductor winding are adjacent to each other.

8. The integrated circuit of claim 3 , wherein the source degeneration inductor is implemented by a spiral winding, comprising three terminals, with one terminal thereof in the middle of the spiral winding and the other two terminals at substantially a same distance from the middle terminal, wherein the middle terminal is connected to ground and the other two terminals are connected to source terminals of the transistors of the transistor pair, wherein the source degeneration inductor is fabricated on the empty space encompassed by the balun.

9. The integrated circuit of claim 8 , wherein the flowing currents are capable of enhancing an inducting effect of the degeneration inductor winding.

10. The integrated circuit of claim 1 , wherein the balun and the degeneration inductor winding are on a same layer in the IC.

11. The integrated circuit of claim 1 , wherein the balun and the degeneration inductor winding are on different layers in the IC.

12. The integrated circuit of claim 1 , wherein the degeneration inductor winding comprises three terminals, with one terminal thereof being connected to ground, and the other two being connected to the transistor pair.

13. The integrated circuit of claim 1 , wherein the transistor pair is a MOS transistor pair, the secondary winding is connected to gate terminals of the MOS transistor pair, the degeneration inductor winding is connected to source terminals of the MOS transistor pair.

14. The integrated circuit of claim 1 , wherein the first and the second winding comprise different numbers of turns, and the balun is adapted to provide a voltage gain to the input signal.

15. A transceiver, comprising:

a balun, having an outer boundary, comprising:

a primary winding, adapted to receive an input signal; and

a secondary winding, magnetically coupled to the primary winding, adapted to convert the input signal into a differential form; and

a receiver, comprising:

a differential amplifier, adapted to connect to the secondary winding and amplify the input signal; and

a source degeneration inductor, connected to the differential amplifier, located within the outer boundary of the balun, wherein the source degeneration inductor is formed such that a mutual inductance between the source degeneration inductor and the secondary winding, whereby current flowing in the secondary winding has a direction the same as current flowing in the source degeneration inductor.

16. The transceiver of claim 14 , further comprising a transmitter, adapted to amplify an output signal, wherein the balun is further adapted to convert the output signal into a single-ended form.

17. The transceiver of claim 14 , wherein the balun further has an inner boundary, and the source degeneration inductor is further encompassed by the inner boundary of the balun.

18. The transceiver of claim 14 , wherein each of the secondary winding and the degeneration inductor has one turn in parallel to each other, and the parallel turns of the secondary winding and the degeneration inductor winding have a spacing therebetween.

19. The transceiver of claim 18 , wherein the spacing is arranged to increase a magnetic coupling effect between the secondary winding and the degeneration inductor.

20. The transceiver of claim 15 , wherein the source degeneration inductor is implemented by a spiral winding, comprising three terminals, with one terminal thereof in the middle of the spiral winding and the other two terminals at substantially a same distance from the middle terminal, wherein the middle terminal is connected to ground and the other two terminals are connected to source terminals of the transistors of the transistor pair, wherein the source degeneration inductor is fabricated on the empty space encompassed by the balun.