Integrated CMOS TIA and DSP for Low-Noise Optical Receivers

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Solution Overview

Problem

Current optical modules with stand-alone TIAs are cost and power intensive, and integrating CMOS TIAs with DSPs for high-speed applications results in weak performance due to interconnection-related issues, limiting their use in high-end, ultra-high-speed optical modules.

Innovation Solution

Integrating CMOS TIA circuits with DSPs on a single chip, eliminating interconnections and allowing for adaptive adjustments in bandwidth, power supply, and gain allocation to optimize performance and reduce noise and harmonic distortion, enabling use in high-speed applications like 400G optical modules.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If stand-alone bipolar TIA is used in optical modules, then performance is maintained, but cost and power consumption increase

Engineering Contradiction:

ImproveperformanceVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent merges the TIA circuit and DSP circuit into a single integrated chip, eliminating the need for separate bipolar TIA components. This integration allows the system to maintain high performance while reducing power consumption by eliminating redundant circuitry and optimizing resource sharing between analog and digital domains.

Inventive Principle:

Principle #5Merging (Combining)

2Device complexity

If CMOS TIA is integrated with DSP, then cost and footprint are reduced, but performance becomes weak due to interconnection issues

Engineering Contradiction:

ImproveintegrationVSAvoidperformance

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent integrates CMOS TIA and DSP circuits on the same chip with optimized interconnections, eliminating the need for external bond wires and PCB traces. This merger maintains signal integrity while achieving the cost and footprint benefits of integration.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces carefully designed interconnection structures that act as intermediaries between the CMOS TIA and DSP circuits, minimizing signal degradation and maintaining performance despite the integration challenges.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If stand-alone TIA and DSP are used with interconnections, then performance is maintained, but device footprint and cost increase

Engineering Contradiction:

ImproveperformanceVSAvoidfootprint

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent combines separate TIA and DSP components into a single integrated chip, dramatically reducing the device footprint by eliminating the need for multiple discrete components, bond wires, and PCB routing space while maintaining performance through optimized on-chip interconnections.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS11722109B1Integrated transimpedance amplifier with a digital signal processor for high-speed optical receivers

Publication Date: 2023.08.08 AVAGO TECHNOLOGIES INTERNATIONAL SALES PTE LTD

AI summary

An optical module includes an optical receiver with a complementary metal-oxide semiconductor (CMOS) transimpedance amplifier (TIA) and a digital signal processing (DSP) circuit. The DSP circuit is integrated with the CMOS TIA and facilitates adaptability of the CMOS TIA, and the CMOS TIA can adapt by using information provided by the DSP circuit.