Optical Receiver TIA Circuit for Wider Bandwidth in Less Chip Area
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Solution Overview
Problem
Existing optical receivers face challenges in increasing bandwidth while minimizing chip area, as inductive peaking technology occupies significant space, reducing efficiency in multistage configurations.
Innovation Solution
The optical receiver design replaces inductors with resistors in transimpedance and limiting amplifiers, using feedback and gate resistors to adjust zero points and bandwidth, and shares resistors between amplifiers to improve bandwidth without using inductors, thereby reducing chip area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If inductive peaking technology is used to increase bandwidth, then bandwidth is improved, but chip area is greatly increased due to inductor occupation
Solution Approach 1:
The patent changes the circuit parameters by replacing inductors with resistors and adjusting resistance values (R1, R2, R3, R4) to achieve bandwidth enhancement without the area penalty of inductors. The resistance ratios are specifically tuned to create zero points that improve bandwidth while maintaining compact chip area.
Solution Approach 2:
The patent extracts and removes the inductor component from the circuit design entirely, replacing it with resistor-based networks. This eliminates the area-consuming inductive elements while achieving the desired bandwidth improvement through alternative circuit topologies involving operational amplifiers and resistor combinations.
2Speed
If inductors are used in each stage of multistage limiting amplifier, then bandwidth may be improved, but chip area efficiency is greatly reduced
Solution Approach 1:
The patent merges the bandwidth enhancement function into a unified resistor-based network that serves multiple amplifier stages simultaneously. Instead of placing inductors in each stage, a shared resistor network (R1-R4) provides bandwidth improvement across the entire multistage limiting amplifier, significantly improving chip area efficiency.
Solution Approach 2:
The resistor network configured in the patent serves multiple functions: it provides bandwidth enhancement, sets gain characteristics, and stabilizes the multistage amplifier simultaneously. This multi-functional approach eliminates the need for separate inductive peaking components in each stage, improving overall chip area efficiency.
Data Source
AI summary
An optical receiver includes a transimpedance amplifier that converts a current signal corresponding to an optical signal into a voltage signal. The transimpedance amplifier includes an input terminal receiving the current signal, an output terminal outputting the voltage signal, an inverting circuit including a pull-up device that pull-up drives the voltage signal of the output terminal according to the current signal, and a pull-down device that pull-down drives the voltage signal of the output terminal according to the current signal, a feedback resistor electrically connected between the input and output terminals, a first resistor electrically connected between the input terminal and the pull-up device, and a second resistor electrically connected between the input terminal and the pull-down device.