Design Considerations of a Sub-50 {\mu}W Receiver Front-end for Implantable Devices in MedRadio Band

TL;DR

This paper analyzes and designs a sub-50μW receiver front-end for implantable devices, achieving high data rates with ultra-low power consumption suitable for medical applications.

Contribution

It introduces a mixer-first architecture with specific components optimized for ultra-low power, demonstrating feasibility of high data-rate communication within 50μW power constraints.

Findings

Achieves 10Mbps data rate at <5pJ/bit energy efficiency.

Identifies active matching and RF gain as power prohibitive in low-power design.

Proposes a novel mixer-first architecture suitable for implantable medical devices.

Abstract

Emerging health-monitor applications, such as information transmission through multi-channel neural implants, image and video communication from inside the body etc., calls for ultra-low active power (<50${\mu}$W) high data-rate, energy-scalable, highly energy-efficient (pJ/bit) radios. Previous literature has strongly focused on low average power duty-cycled radios or low power but low-date radios. In this paper, we investigate power performance trade-off of each front-end component in a conventional radio including active matching, down-conversion and RF/IF amplification and prioritize them based on highest performance/energy metric. The analysis reveals 50${\Omega}$ active matching and RF gain is prohibitive for 50${\mu}$W power-budget. A mixer-first architecture with an N-path mixer and a self-biased inverter based baseband LNA, designed in TSMC 65nm technology show that sub 50${\mu}$W performance can be achieved up to 10Mbps (< 5pJ/b) with OOK modulation.