A 8.6 μW 3-bit programmable gain amplifier for multiplexed-input neural recording systems.

Area of Science:

• Integrated Circuits
• Biomedical Engineering
• Neuroscience

Background:

• Multi-channel neural recording systems require amplifiers to adjust signal gain.
• Existing amplifiers often have high power consumption, limiting system miniaturization and channel count.
• Energy efficiency is critical for implantable and wearable neural interfaces.

Purpose of the Study:

• To design and characterize a fully-integrated, low-power 3-bit programmable-gain amplifier (PGA).
• To optimize the PGA for maximum energy efficiency in neural recording applications.
• To demonstrate the PGA's effectiveness as a second-stage amplifier in a multi-channel system.

Main Methods:

• A novel design strategy optimizing slew rate, gain, and phase margin for energy efficiency.
• Detailed analysis, simulation, and measurement of the PGA.
• Implementation within a multiplexed 16-channel neural recording system.

Main Results:

• The PGA achieves an ultra-low power consumption of 8.66 μW from a 1-V supply.
• Power consumption is an order of magnitude lower than previous designs.
• Each channel incurs negligible overhead: 0.54 μW power and <0.002 mm² area.

Conclusions:

• The developed PGA offers significant power savings for neural recording systems.
• The design provides full gain control flexibility with minimal area and power overhead.
• This technology enables more scalable and efficient multi-channel neural interfaces.