A 4.5 μW Miniaturized 3-Channel Wireless Intra-Cardiac Acquisition System.

Area of Science:

• Biomedical Engineering
• Electrical Engineering
• Microelectronic Systems

Background:

• Wireless intra-cardiac monitoring systems are crucial for diagnosing and managing cardiovascular conditions.
• Existing systems face challenges with power consumption, size, and signal integrity.
• Miniaturization and improved analog front-end performance are key for next-generation implantable devices.

Purpose of the Study:

• To design and validate a System-on-Chip (SoC) for wireless intra-cardiac monitoring.
• To achieve high-fidelity signal acquisition with low power consumption and reduced form factor.
• To enhance the robustness of the system against environmental and process variations.

Main Methods:

• Development of a three-channel analog front-end with a resistance boosting technique for reduced non-linearity and size.
• Implementation of a pulse-width modulator with output-frequency offset and temperature calibration algorithms.
• Integration of inductive data telemetry and an ASK-PWM modulator for wireless data transmission.

Main Results:

• Achieved total harmonic distortion below 0.1% due to the resistance boosting technique.
• Front-end channel exhibits an effective number of bits of 8.9 and input-referred noise < 2.7 μV_rms.
• The SoC consumes 4.5 μW, occupies 1.125 mm², and operates at 13.56 MHz.

Conclusions:

• The developed SoC is suitable for wireless intra-cardiac monitoring systems, offering improved performance and miniaturization.
• The resistance boosting technique effectively reduces non-linearity and component size.
• Temperature and process calibration ensure reliable modulator operation, paving the way for advanced implantable cardiac devices.