Semiconductor device
When a power amplifier mounted in mobile communications equipment, such as a mobile-phone, is composed of a balanced amplifier, technology with which the loss of the electric power composition in a power combiner can be reduced is provided. According to the technical idea of the present embodiment, by dividing an isolation capacitor element into two capacitor elements with high symmetry and coupled in parallel, it is possible to make almost equal parasitic capacitance arising from these capacitor elements, even when the capacitor elements are formed as interlayer capacitor elements of the wiring substrate.
1. A semiconductor device comprising:
a negative path;
a positive path: and
a power combiner,
the negative path including:
(a1) a first phase shifter;
(b1) a first amplifier coupled to an output of the first phase shifter;
(c1) a second phase shifter coupled to an output of the first amplifier, and
(d1) a first terminal;
the positive path including:
(a2) a third phase shifter;
(b2) a second amplifier coupled to an output of the third phase shifter;
(c2) a fourth phase shifter coupled to an output of the second amplifier, and
(d2) a second terminal;
the power combiner being operable to combine a first signal output from the second phase shifter via the first terminal, and a second signal output from the fourth phase shifter via the second terminal and having a same phase as the first signal,
wherein the power combiner is a Webb-type power combiner, and
wherein the Webb-type power combiner comprises:
a resistor element provided between the negative path and the positive path; and
an even number of capacitor elements coupled in parallel, each of the capacitor elements being coupled between the first terminal of the negative path and the second terminal of the positive path.
2. The semiconductor device according to claim 1 ,
wherein the even number of capacitor elements comprise a first capacitor element and a second capacitor element.
3. The semiconductor device according to claim 2 ,
wherein the first capacitor element comprises a first upper electrode formed in a first layer of a multilayer wiring board, a first lower electrode formed in a second layer disposed lower than the first layer of the multilayer wiring board, and a capacity insulating layer sandwiched between the first layer and the second layer, and
wherein the second capacitor element comprises a second upper electrode formed in the first layer of the multilayer wiring board, a second lower electrode formed in the second layer of the multilayer wiring board, and the capacity insulating layer.
4. The semiconductor device according to claim 3 ,
wherein the value of capacitance of the first capacitor element and the value of capacitance of the second capacitor element are substantially equal.
5. The semiconductor device according to claim 3 ,
wherein the difference in area of the first lower electrode and the second lower electrode is smaller than the difference in area of the first upper electrode and the first lower electrode.
6. The semiconductor device according to claim 5 ,
wherein the area of the first lower electrode and the area of the second lower electrode are substantially equal.
7. The semiconductor device according to claim 3 ,
wherein the difference in shape of the first lower electrode and the second lower electrode is smaller than the difference in shape of the first upper electrode and the first lower electrode.
8. The semiconductor device according to claim 7 ,
wherein the shape of the first lower electrode and the shape of the second lower electrode are substantially equal.
9. The semiconductor device according to claim 3 ,
wherein the symmetric relation existing between the shape of the first lower electrode and the shape of the second lower electrode is higher than the symmetric relation existing between the shape of the first upper electrode and the shape of the first lower electrode.
10. The semiconductor device according to claim 3 ,
wherein the difference in area of the first upper electrode and the second upper electrode is smaller than the difference in area of the first upper electrode and the first lower electrode.
11. The semiconductor device according to claim 10 ,
wherein the area of the first upper electrode and the area of the second upper electrode are substantially equal.
12. The semiconductor device according to claim 3 ,
wherein the difference in shape of the first upper electrode and the second upper electrode is smaller than the difference in shape of the first upper electrode and the first lower electrode.
13. The semiconductor device according to claim 3 ,
wherein the symmetric relation existing between the shape of the first upper electrode and the shape of the second upper electrode is higher than the symmetric relation existing between the shape of the first upper electrode and the shape of the first lower electrode.
14. The semiconductor device according to claim 13 ,
wherein the first upper electrode and the second upper electrode satisfy the relation of mirror-image symmetry.
15. The semiconductor device according to claim 3 ,
wherein the distance between the first upper electrode and the first lower electrode and the distance between the second upper electrode and the second lower electrode are substantially equal.
16. The semiconductor device according to claim 3 ,
wherein the potential of the first upper electrode and the potential of the second lower electrode are equipotential, and the Potential of the second upper electrode and the potential of the first lower electrode are equipotential.
17. The semiconductor device according to claim 3 ,
wherein a reference-potential conductor plane to which reference potential is applied is formed in a third layer disposed lower than the second layer of the multilayer wiring board.
18. The semiconductor device according to claim 17 ,
wherein the difference in area of the first lower electrode and the second lower electrode is smaller than the difference in area of the first upper electrode and the first lower electrode, and the distance between the first lower electrode and the reference-potential conductor plane and the distance between the second lower electrode and the reference-potential conductor plane are substantially equal.