A Low-Noise CMOS Transimpedance-Limiting Amplifier for Dynamic Range Extension

Area of Science:

• Electronics Engineering
• Photonics and Optoelectronics

Background:

• LiDAR systems require amplifiers that handle large photocurrents.
• Existing limiting amplifiers can be power-hungry and introduce distortions.

Purpose of the Study:

• To develop a low-noise CMOS transimpedance-limiting amplifier (CTLA) for power-efficient LiDAR sensors.
• To enable automatic photocurrent limiting without signal distortion.

Main Methods:

• A dual-feedback architecture combining passive and active feedback was designed.
• An NMOS switch was integrated for automatic on/off switching based on input current.
• The feedback resistor was optimized for robustness and stability.

Main Results:

• Fabricated CTLA achieved 88.8 dBΩ gain, 629 MHz bandwidth, and 2.31 pA/√Hz noise spectral density.
• Demonstrated automatic limiting for photocurrents up to 1.06 mA_pp.
• Achieved a 56.6 dB input dynamic range with 23.6 mW power dissipation at 1.8 V.

Conclusions:

• The proposed CTLA offers a power-efficient solution for LiDAR sensors.
• The dual-feedback design effectively manages high photocurrents without distortion.
• The compact chip size and performance metrics are suitable for real-world LiDAR applications.