Self biased dual mode differential CMOS TIA for 400G fiber optic links

Patent metadata

Field	Value
Publication number	US-9793863-B2
Application number	US-201614987673-A
Country	US
Kind code	B2
Filing date	Jan 4, 2016
Priority date	Sep 25, 2013
Publication date	Oct 17, 2017
Grant date	Oct 17, 2017

Abstract

A transimpedance amplifier (TIA) device. The device includes a photodiode coupled to a differential TIA with a first and second TIA, which is followed by a Level Shifting/Differential Amplifier (LS/DA). The photodiode is coupled between a first and a second input terminal of the first and second TIAs, respectively. The LS/DA can be coupled to a first and second output terminal of the first and second TIAs, respectively. The TIA device includes a semiconductor substrate comprising a plurality of CMOS cells, which can be configured using 28 nm process technology to the first and second TIAs. Each of the CMOS cells can include a deep n-type well region. The second TIA can be configured using a plurality CMOS cells such that the second input terminal is operable at any positive voltage level with respect to an applied voltage to a deep n-well for each of the plurality of second CMOS cells.

First claim

What is claimed is:

1. A communication system comprising:
a transimpedance amplifier (TIA) device comprising:
a semiconductor substrate comprising a plurality of CMOS cells, each of the CMOS cells comprising a deep n-type well region;
a first TIA comprising a first input terminal and a first output terminal, the first TIA configured using a plurality of first CMOS cells;
a second TIA comprising a second input terminal and a second output terminal, the second TIA configured using a plurality of second CMOS cells such that the second input terminal is operable at any positive voltage level with respect to an applied voltage to a deep n-well for each of the plurality of second CMOS cells;
a photodiode coupled between the first input terminal and the second input terminal; and
a Level Shifting/Differential Amplifier (LS/DA) coupled to the first output terminal and the second output terminal; and
an optical link coupled to the TIA device.

2. The system of claim 1 wherein the photodiode is characterized by a responsivity value ranging from about 0.6 to about 0.9 Amps/Watt.

3. The system of claim 1 wherein the first TIA comprises a VDDL level and a VSSL level; and wherein the second TIA comprises a VDDH level and a VSSH level.

4. The system of claim 1 wherein the plurality of CMOS cells is configured using a 28 nm process technology.

5. The system of claim 1 wherein each of the first TIA and the second TIA is provided with a supply voltage independent of a photodiode differential voltage provided on the first input terminal and the second input terminal.

6. The system of claim 1 wherein each of the first TIA and the second TIA includes a first switch device configured for at least two bit rates.

7. The system of claim 1 wherein the LS/DA comprises an up-shifting device and a down-shifting device configured to mitigate any mismatch in data bits between the first TIA and the second TIA; wherein the LS/DA comprises a differential amplifier having a differential voltage output.

8. The system of claim 1 wherein the LS/DA comprises an up-shifting device and a down-shifting device configured to mitigate any mismatch in data bits between the first TIA and the second TIA; and
further comprising a gain amplifier configured to correct any losses provided by either the up-shifting device or the down-shifting device; wherein the LS/DA comprises a differential amplifier having a differential voltage output.

9. The system of claim 8 further comprising a level shifter configured with the LS/DA.

10. The system of claim 1 further comprising an AC source coupled to a first capacitor and configured to the first output terminal; and the AC source coupled to a second capacitor and configured to the second outputer terminal.

11. The system of claim 1 further comprising a clock data recovery module coupled to each of the first TIA and the second TIA, the clock data recovery module configured with the plurality of CMOS cells.

12. The system of claim 1 further comprising a digital signal processor module coupled to each of the first TIA and the second TIA.

13. A system, the system comprising:
a semiconductor substrate comprising a plurality of CMOS cells, each of the CMOS cells comprising a deep n-type well region;
a transimpedance amplifier (TIA) module comprising:
a first TIA comprising a first input terminal and a first output terminal, the first TIA configured using a plurality of first CMOS cells;
a second TIA comprising a second input terminal and a second output terminal, the second TIA configured using a plurality of second CMOS cells such that the second input terminal is operable at any positive voltage level with respect to an applied voltage to a deep n-well for each of the plurality of second CMOS cells;
a photodiode coupled between the first input terminal and the second input terminal, the photodiode being a discrete device and separate from the first and second TIAs;
a Level Shifting/Differential Amplifier (LS/DA) coupled to the first output terminal and the second output terminal; and

whereupon the first input terminal and the second input terminal are provided with a differential voltage ranging from about 1V to about 5V;
a Clock and Data Recovery (CDR) module coupled to the TIA module, and configured with a plurality of CMOS cells; and
a communication link.

14. The system of claim 13 wherein the photodiode is characterized by a responsivity value ranging from about 0.6 to about 0.9 Amps/Watt.

15. The system of claim 13 wherein the first TIA comprises a VDDH level and a VSSH level; and wherein the second TIA comprises a VDDL level and a VSSL level.

16. The system of claim 13 wherein the plurality of CMOS cells is configured using a 28 nm process technology.

17. The system of claim 13 wherein each of the first TIA and the second TIA is provided with a supply voltage independent of a photodiode differential voltage provided on the first input terminal and the second input terminal.

18. The system of claim 13 wherein each of the first TIA and the second TIA includes a first switch device configured for at least two bit rates.

19. The system of claim 13 wherein the LS/DA comprises an up-shifting device and a down-shifting device configured to mitigate any mismatch in data bits between the first TIA and the second TIA; wherein the LS/DA comprises a differential amplifier having a differential voltage output.

20. The system of claim 13 wherein the LS/DA comprises an up-shifting device and a down-shifting device configured to mitigate any mismatch in data bits between the first TIA and the second TIA; and
further comprising a gain amplifier configured to correct any losses provided by either the up-shifting device or the down-shifting device; wherein the LS/DA comprises a differential amplifier having a differential voltage output.

21. The system of claim 20 further comprising a level shifter configured with the LS/DA.

22. The system of claim 13 further comprising an AC source coupled to a first capacitor and configured to the first output terminal; and the AC source coupled to a second capacitor and configured to the second output terminal.

23. The system of claim 13 further comprising a digital signal processor module coupled to each of the first TIA and second TIA, and configured with a plurality of CMOS cells.

Assignees

• Inphi Corp

Inventors

• Shringarpure Rahul
• Broekaert Tom Peter Edward
• Mahajan Gaurav

Classifications

• H03F2200/555

  A voltage generating circuit being realised for biasing different circuit elements · CPC title

• H03F3/45475

  using IC blocks as the active amplifying circuit · CPC title

• H03F1/0205

  in transistor amplifiers · CPC title

• H03F3/082 Primary

  with FET's (H03F3/085 takes precedence) · CPC title

• H03F3/087

  with IC amplifier blocks (H03F3/085 takes precedence) · CPC title