Radio frequency amplifiers having improved shunt matching circuits
RF amplifiers are provided that include a submount such as a thermally conductive flange. A dielectric substrate is mounted on an upper surface of the submount, the dielectric substrate having a first outer sidewall, a second outer sidewall that is opposite and substantially parallel to the first outer sidewall, and an interior opening. An RF amplifier die is mounted on the submount within the interior opening of the dielectric substrate, where a longitudinal axis of the RF amplifier die defines a first axis. The RF amplifier die is positioned so that a first angle defined by the intersection of the first axis with the first outer sidewall is between 5° and 45°. The dielectric substrate may be a ceramic substrate or a dielectric layer of a printed circuit board.
1. A radio frequency (“RF”) amplifier, comprising:
a submount;
a dielectric substrate mounted on an upper surface of the submount, the dielectric substrate having a first outer sidewall, a second outer sidewall that is opposite and substantially parallel to the first outer sidewall, and an interior opening;
conductive leads on the dielectric substrate; and
an RF amplifier die mounted on the submount within the interior opening of the dielectric substrate, a longitudinal axis of the RF amplifier die defining a first axis,
wherein a first angle defined by the intersection of the first axis with the first outer sidewall is between 5° degrees and 45°.
2. The RF amplifier of claim 1 , further comprising an input impedance matching capacitor die that is mounted on the upper surface of the submount within the interior opening in the dielectric substrate.
3. The RF amplifier of claim 2 , wherein a longitudinal axis of the input impedance matching capacitor die defines a third axis, and the first axis intersects the third axis at a third angle that is between 5° and 45°.
4. The RF amplifier of claim 2 , further comprising a plurality of first bond wires that electrically connect the input impedance matching capacitor die to the RF amplifier die, wherein a maximum height of a first of the first bond wires above the upper surface of the submount is less than a maximum height of a second of the first bond wires above the upper surface of the submount.
5. The RF amplifier of claim 4 , wherein all of the first bond wires have substantially a same inductance.
6. The RF amplifier of claim 5 , wherein the first of the first bond wires is closer to a center of the submount than is the second of the first bond wires.
7. The RF amplifier of claim 2 , further comprising an output impedance matching capacitor die that is mounted on the upper surface of the submount within the interior opening in the dielectric substrate, wherein a longitudinal axis of the output impedance matching capacitor die defines a fifth axis, and the fifth axis intersects an axis defined by the first outer sidewall is at an angle of between 45° and 80°.
8. The RF amplifier of claim 1 , wherein the RF amplifier die is a first RF amplifier die, the RF amplifier further comprising a second RF amplifier die that has a longitudinal axis that defines a second axis, wherein the first and second axes intersect at an angle of between 90° and 170°.
9. A radio frequency (“RF”) amplifier, comprising:
a submount;
an RF amplifier die mounted on the submount, a longitudinal axis of the RF amplifier die defining a first axis;
an input impedance matching capacitor die that is mounted on the upper surface of the submount, a longitudinal axis of the input impedance matching capacitor die defining a third axis; and
a plurality of bond wires that electrically connect the input impedance matching capacitor die to the RF amplifier die,
wherein an angle defined by the intersection of the first axis and the third axis is between 5° and 45°.
10. The RF amplifier of claim 9 , further comprising a printed circuit board having an interior opening mounted on an upper surface of the submount, wherein the RF amplifier die and the input impedance matching capacitor die are both within the interior opening in the printed circuit board.
11. The RF amplifier of claim 10 , wherein respective heights of the plurality of bond wires decrease the closer the bond wires are to the center of the submount.
12. The RF amplifier of claim 11 , wherein the RF amplifier die is a first RF amplifier die, the RF amplifier further comprising a second RF amplifier die that has a longitudinal axis that defines a second axis, wherein the first and second axes intersect at an angle of between 90° and 170°.
13. The RF amplifier of claim 9 , further comprising:
a first dielectric substrate with conductive paths thereon on a first side of the RF amplifier die;
a second dielectric substrate with conductive paths thereon on a second side of the RF amplifier die that is opposite the first side at least one input flange that extends between the first dielectric substrate and the submount; and
at least one output flange that extends between the submount and the second dielectric substrate.
14. The RF amplifier of claim 9 , further comprising a first leadframe that is coupled to an input of the RF amplifier die and a second leadframe that is coupled to an output of the RF amplifier die.
15. The RF amplifier of claim 14 , wherein the RF amplifier die and portions of the first and second lead frames and the submount are encapsulated in an overmold package.
16. A radio frequency (“RF”) amplifier, comprising:
a printed circuit board;
a plurality of packaged integrated circuit die mounted on or in the printed circuit board, the packaged integrated circuit die including an RF amplifier die and an impedance matching capacitor die that is electrically connected to the RF amplifier die, where a longitudinal axis of the RF amplifier die defines a first axis and a longitudinal axis of the impedance matching capacitor die defines a second axis that intersects the first axis at an oblique angle.
17. The RF amplifier of claim 16 , wherein the impedance matching capacitor die is an input impedance matching capacitor die.
18. The RF amplifier of claim 17 , further comprising a plurality of first bond wires that electrically connect the input impedance matching capacitor die to the RF amplifier die, wherein a maximum height of a first of the first bond wires above the upper surface of the submount is less than a maximum height of a second of the first bond wires above the upper surface of the submount.
19. The RF amplifier of claim 18 , wherein the first of the first bond wires is closer to a center of the submount than is the second of the first bond wires.
20. The RF amplifier of claim 17 , further comprising an output impedance matching capacitor die that is mounted on or in the printed circuit board and that is electrically connected to the RF amplifier die, wherein a longitudinal axis of the output impedance matching capacitor die defines a third axis, and the third axis intersects the first axis at an angle of between 30° and 60°.