Method and system for reducing parasitic feedback and parasitic resonances in high-gain transimpedance amplifiers
View Patent ↗Method and system for reducing parasitic feedback and resonances in high-gain transimpedance amplifiers. In a first embodiment of the present invention, a resistive layer is implemented in the gaps of a high-gain transimpedance amplifier's metallic planes. In a second embodiment of the present invention, a resistive layer is implemented underneath a high-gain transimpedance amplifier's ground plane, vias are implemented to create contact between the resistive layer and the ground plane.
1. A high-gain transimpedance amplifier, comprising:
a metallic ground plane; and
a layer of resistive material implemented below the metallic ground plane;
wherein there is no direct electrical contact between the metallic ground plane and the layer of resistive material;
such that said resistive material absorbs RF energy that might otherwise result in parasitic feedback between said amplifier's output and input.
2. The amplifier of claim 1 , further comprising a layer of dielectric implemented below the layer of resistive material.
3. The amplifier of claim 1 , wherein the metallic ground plane comprises gold.
4. The amplifier of claim 1 , wherein the metallic ground plane comprises aluminum.
5. The amplifier of claim 1 , wherein the metallic ground plane comprises copper.
6. The amplifier of claim 1 , wherein the resistive material comprises Tantalum-Nitride.
7. The amplifier of claim 1 , wherein the resistive material comprises Nickel-Chrome.
8. A high-gain transimpedance amplifier, comprising:
a ground plane comprising a first layer of metallic material and a second layer of metallic material, wherein the first layer of metallic material lies adjacent to the second layer of metallic material; and
a layer of resistive material implemented below the ground plane;
wherein there is no direct electrical contact between the first layer of metallic material and the layer of resistive material, wherein there is no direct electrical contact between the second layer of metallic material and the layer of resistive material;
such that said resistive material absorbs RF energy that might otherwise result in parasitic feedback between said amplifier's output and input.
9. The amplifier of claim 8 , wherein the first layer of metallic material and the second layer of metallic material lie parallel on the same plane.
10. A high-gain transimpedance amplifier, comprising:
a ground plane comprising a first layer of metallic material and a second layer of metallic material, wherein the first layer of metallic material lies adjacent to the second layer of metallic material; and
a layer of resistive material implemented below the ground plane;
wherein there is no direct contact between the first layer of metallic material and the layer of resistive material, wherein there is no direct contact between the second layer of metallic material and the layer of resistive material; and
wherein a gap or electrical disconnect lies between the first layer of metallic material and the second layer of metallic material.
11. The amplifier of claim 8 , further comprising a layer of dielectric implemented below the layer of resistive material.
12. A high-gain transimpedance amplifier, comprising:
a ground plane comprising a first layer of metallic material and a second layer of metallic material, wherein the first layer of metallic material lies adjacent to the second layer of metallic material with a gap or electrical disconnect between the first layer of metallic material and the second layer of metallic material; and
a layer of resistive material implemented in the gap between the first layer of metallic material and the second layer of metallic material;
wherein there is no direct contact between the first layer of metallic material and the layer of resistive material, wherein there is no direct contact between the second layer of metallic material and the layer of resistive material.
13. The amplifier of claim 12 , wherein the first layer of metallic material and the second layer of metallic material lie parallel on the same plane.
14. The amplifier of claim 12 , further comprising a layer of dielectric implemented below the layer of resistive material and the ground plane.
15. A high-gain transimpedance amplifier, comprising:
a ground plane comprising a first layer of metallic material and a second layer of metallic material, wherein the first layer of metallic material lies adjacent to the second layer of metallic material with a gap or electrical disconnect between the first layer of metallic material and the second layer of metallic material; and
a layer of resistive material implemented in the gap between the first layer of metallic material and the second layer of metallic material;
wherein a single or a plurality of vias are implemented between the ground plane and the layer of resistive material to provide contact between the ground plane and the layer of resistive material wherein amount of the vias is not two.
16. A high-gain transimpedance amplifier, comprising:
a ground plane comprising a first layer of metallic material, a second layer of metallic material, a third layer of metallic material, and a fourth layer of metallic material, wherein the first layer of metallic material lies adjacent to the second layer of metallic material and the third layer of metallic material lies adjacent to the fourth layer of metallic material; and
a layer of resistive material implemented below the ground plane;
wherein there is no direct electrical contact between the metallic ground plane layers and the layer of resistive material;
such that said resistive material absorbs RF energy that might otherwise result in parasitic feedback between said amplifier's output and input.
17. The amplifier of claim 16 , wherein the first layer of metallic material, the second layer of metallic material, the third layer of metallic material, and the fourth layer of metallic material all lie parallel on the same plane.
18. A high-gain transimpedance amplifier, comprising:
a ground plane comprising a first layer of metallic material, a second layer of metallic material, a third layer of metallic material, and a fourth layer of metallic material, wherein the first layer of metallic material lies adjacent to the second layer of metallic material and the third layer of metallic material lies adjacent to the fourth layer of metallic material; and
a layer of resistive material implemented below the ground plane;
wherein a gap or electrical disconnect lies between the first layer of metallic material and the second layer of metallic material.
19. A high-gain transimpedance amplifier, comprising:
a ground plane comprising a first layer of metallic material, a second layer of metallic material, a third layer of metallic material, and a fourth layer of metallic material, wherein the first layer of metallic material lies adjacent to the second layer of metallic material and the third layer of metallic material lies adjacent to the fourth layer of metallic material; and
a layer of resistive material implemented below the ground plane;
wherein a gap or electrical disconnect lies between the third layer of metallic material and the fourth layer of metallic material.
20. The amplifier of claim 16 , further comprising a layer of dielectric implemented below the layer of resistive material.
21. A high-gain transimpedance amplifier, comprising:
a ground plane comprising a first layer of metallic material, a second layer of metallic material, a third layer of metallic material, and a fourth layer of metallic material, wherein the first layer of metallic material lies adjacent to the second layer of metallic material with a first gap or electrical disconnect between the first layer of metallic material and the second layer of metallic material, and the third layer of metallic material lies adjacent to the fourth layer of metallic material with a second gap or electrical disconnect between the third layer of metallic material and the fourth layer of metallic material; and
a layer of resistive material implemented in the gap between the first layer of metallic material and the second layer of metallic material and in the gap between the third layer of metallic material and the fourth layer of metallic material.
22. The amplifier of claim 21 , wherein the first layer of metallic material, the second layer of metallic material, the third layer of metallic material, and the fourth layer of metallic material all lie parallel on the same plane.
23. The amplifier of claim 21 , further comprising a layer of dielectric implemented below both the layer of resistive material and the ground plane.
24. The amplifier of claim 21 , wherein the layer of resistive material is in direct contact with the ground plane.