Ultra-broadband transimpedance amplifiers (tia) for optical fiber communications

Patent metadata

Field	Value
Publication number	US-10243523-B2
Application number	US-201715725212-A
Country	US
Kind code	B2
Filing date	Oct 4, 2017
Priority date	Oct 4, 2016
Publication date	Mar 26, 2019
Grant date	Mar 26, 2019

Abstract

Design of ultra broadband transimpedance amplifiers (TIA) for optical fiber communications is disclosed. In one embodiment, a TIA comprises a gm-boosted dual-feedback common-base stage, a level shifter and an RC-degenerated common-emitter stage, and a first emitter-follower stage, wherein the first emitter follower stage is inductively degenerated. An output of the TIA is buffered using a second emitter-follower stage.

First claim

The invention claimed is:

1. A transimpedance amplifier (TIA), comprising:
a g m -boosted dual-feedback common-base stage;
a level shifter and an RC-degenerated common-emitter stage; and
a first emitter-follower stage, wherein the first emitter follower stage is inductively degenerated;
wherein an output of the TIA is buffered using a second emitter-follower stage.

2. The TIA of claim 1 , wherein the g m -boosted dual-feedback common-base stage comprises:
a shunt-in-shunt-out positive feedback realized with a mutually coupled inductor pair comprising a first inductor (L 2 ) and a second inductor (L 3 ); and
a local resistive shunt-in-shunt-out negative feedback comprising a first resistor (R 2 ).

3. The TIA of claim 2 , wherein the g m -boosted dual-feedback common-base stage further comprises:
a g m -boosting transistor (B 1 ) driving a series load comprising a second resistor (R 1 ) and a third inductor (L 1 ).

4. The TIA of claim 1 , wherein the RC-degenerated common-emitter stage comprises:
a level shifter comprising a first transistor (B 5 ) and a third resistor (R 5 ); and
an emitter degeneration stage comprising a second transistor (B 6 ), a fourth resistor (R 6 ), and a varactor comprising a first capacitor (C 6 ).

5. The TIA of claim 4 , wherein the RC-degenerated common-emitter stage introduces a zero pole at a first frequency, wherein the first frequency is 1/(2πR 6 C 6 ).

6. The TIA of claim 4 , wherein the RC-degenerated common-emitter stage introduces a high frequency pole at a second frequency, wherein the second frequency is (1+g m 6 R 6 )/2πR 6 C 6 .

7. The TIA of claim 1 , wherein the first emitter-follower stage comprises:
a fourth inductor (L 4 ); and
a fifth inductor (L 5 );
wherein the fourth inductor (L 4 ) introduces a series peaking behavior to the output of the transimpedance amplifier (TIA); and
wherein the fifth inductor (L 5 ) degenerates the first emitter-follower stage.

8. A method of converting an input current signal to an output voltage signal using a transimpedance amplifier (TIA), the method comprising:
applying the input current signal to a g m -boosted dual-feedback common-base stage of the TIA;
electrically coupling the g m -boosted dual-feedback common-base stage of the TIA with a level shifter and RC-degenerated common-emitter stage of the TIA;
electrically coupling the level shifter and RC-degenerated common-emitter stage with a first emitter-follower stage of the TIA, wherein the first emitter follower stage is inductively degenerated; and
buffering the output voltage signal using a second emitter-follower stage.

9. The method of claim 8 , wherein the g m -boosted dual-feedback common-base stage of the TIA comprises:
a shunt-in-shunt-out positive feedback realized with a mutually coupled inductor pair comprising a first inductor (L 2 ) and a second inductor (L 3 ); and
a local resistive shunt-in-shunt-out negative feedback comprising a first resistor (R 2 ).

10. The method of claim 9 , wherein the g m -boosted dual-feedback common-base stage of the TIA further comprises:
a g m -boosting transistor (B 1 ) driving a series load comprising a second resistor (R 1 ) and a third inductor (L 1 ).

11. The method of claim 8 , wherein the RC-degenerated common-emitter stage of the TIA comprises:
a level shifter comprising a first transistor (B 5 ) and a third resistor (R 5 ); and
an emitter degeneration stage comprising a second transistor (B 6 ), a fourth resistor (R 6 ), and a varactor comprising a first capacitor (C 6 ).

12. The method of claim 11 , wherein the RC-degenerated common-emitter stage of the TIA introduces a zero pole at a first frequency, wherein the first frequency is 1/(2πR 6 C 6 ).

13. The method of claim 12 , wherein the RC-degenerated common-emitter stage of the TIA introduces a high frequency pole at a second frequency, wherein the second frequency is (1+g m 6 R 6 )/2πR 6 C 6 .

14. The method of claim 8 , wherein the first emitter-follower stage of the TIA comprises:
a fourth inductor (L 4 ); and
a fifth inductor (L 5 );
wherein the fourth inductor (L 4 ) introduces a series peaking behavior to the output of the transimpedance amplifier (TIA); and
wherein the fifth inductor (L 5 ) degenerates the first emitter-follower stage.

Assignees

• Univ California

Inventors

• Heydari Payam
• Mohammadnezhad Seyed Mohammad Hossein
• Karimi Bidhendi Alireza
• Green Michael M
• Howard David
• Preisler Edward

Classifications

• H03F2203/5036

  the source follower has a resistor in its source circuit · CPC title

• H03F1/42

  Modifications of amplifiers to extend the bandwidth · CPC title

• H03F1/347 Primary

  using transformers · CPC title

• H03F3/08

  controlled by light · CPC title

• H03F3/3432

  with bipolar transistors · CPC title