Mixed-Signal PCB Design & Analog Front-End Design
Transmissive Pulse Oximeter
• Managed a 4-person engineering team, managing timelines and design reviews to ensure on-time hardware and firmware integration
• Led schematic capture and board layout of a mixed-signal PCB in Altium Designer, integrating battery charging and an I2C display for real-time SpO2, heart rate, and temperature readings
• Designed a custom analog front-end, implementing a precision transimpedance amplifier, 3rd-order Sallen-Key filter, and 380x gain stage to process nano-amp photodiode signals
• Engineered a precision bandgap reference and PTAT circuit for LED thermal drift compensation, achieving 0.5°C accuracy and validating a constant voltage within 1mV over a 20°C to 50°C sweep
• Developed embedded C/C++ firmware, utilizing DSP and an adaptive peak detection algorithm to achieve SpO2 accuracy within 2% and heart rate tracking within 3 bpm