MAXREFDES220# – Cuffless Blood Pressure Monitoring with Optical Sensors

Introducing the MAXREFDES220# Cuffless Blood Pressure Monitor

Maxim Integrated’s MAXREFDES220# brings cuffless blood pressure measurement to the consumer market. By combining a high‑sensitivity optical sensor, a dedicated microcontroller hub, and a validated algorithm, the reference design delivers reliable systolic and diastolic readings without the bulk of traditional cuff‑based devices.

Why Cuffless Monitoring Matters

Modern patient care spans home, hospital, and diagnostic settings. Wearable solutions that can accurately track vital signs—particularly blood pressure—enable continuous monitoring, early intervention, and cost‑effective care. Positioning the device on the finger reduces invasiveness while maintaining precision.

Device Architecture

The reference design incorporates the MAX30101 or MAX30102 optical sensor and the MAX32664D sensor hub. Together, they form an integrated system that reads the finger for 30–45 seconds, processing raw photodiode signals with built‑in algorithms.

Figure 1: MAXREFDES220# – ready‑to‑use solution

Accuracy & Regulatory Compliance

• Systolic: Mean error = 1.7 mmHg; Std dev = 7.4 mmHg
• Diastolic: Mean error = 0.1 mmHg; Std dev = 7.6 mmHg
• Class II limits: Mean ≤ 5 mmHg; Std dev ≤ 8 mmHg

Pulse Oximetry & Heart Rate

The MAX30101 module measures oxygen saturation using three wavelengths (660 nm, 940 nm, and 805 nm). Low‑noise photodiodes, high‑impedance analog front‑end, and 16‑bit ADCs enable precise extraction of SpO₂ and pulse rate, even in the presence of motion artifacts.

Embedded Algorithm

The MAX32664D hub runs Maxim’s BPT algorithm, offloading complex processing from the host MCU. This architecture frees system resources and simplifies firmware development while ensuring consistent performance.

Figure 2: System diagram of MAX30101

Benefits for Health Care

Cuffless, finger‑based monitoring supports proactive health management, reduces patient discomfort, and expands continuous data collection beyond clinical settings. Frequent, accurate feedback can motivate healthier lifestyles and early detection of cardiovascular issues.