A 5-nV/√Hz Chopper Negative-R Stabilization Preamplifier for Audio Applications.

Area of Science:

• Electrical Engineering
• Analog Integrated Circuit Design
• Low-Noise Amplifiers

Background:

• Preamplifiers are crucial for amplifying weak audio signals but are often limited by noise and power consumption.
• 1/f noise and thermal noise degrade audio signal quality.
• Maintaining linearity in preamplifiers is essential for accurate audio reproduction.

Purpose of the Study:

• To develop a low-noise and low-power audio preamplifier.
• To mitigate 1/f noise and thermal noise in preamplifiers.
• To improve the linearity of audio preamplifiers.

Main Methods:

• Implementation of a delay-time chopper stabilization (CHS) technique.
• Utilization of a negative-R circuit in an auxiliary amplifier.
• Fabrication using 65 nm complementary metal-oxide semiconductor (CMOS) technology.

Main Results:

• Achieved a signal-to-noise ratio (SNR) of 80 dB over a 20 kHz bandwidth.
• Measured an equivalent-input referred noise of 5 nV/√Hz.
• Demonstrated a noise efficiency factor (NEF) of 1.9.

Conclusions:

• The proposed CHS and negative-R techniques effectively reduce noise and improve linearity.
• The developed preamplifier offers excellent performance with low power consumption (159 µW) and a small area (192 µm²).
• This design is suitable for high-performance audio systems requiring minimal noise and power usage.