MAXREFDES1044: Heart-Rate Monitor Using the MAX30101
|Input Type||VIN (MIN)
The MAX30101 is an integrated pulse oximetry and heartrate monitor module. It includes internal LEDs, photodetectors, optical elements, and low-noise electronics with ambient light rejection. Other Maxim components used in this design include two MAX8892 (a high PSRR, low-dropout, 150mA linear regulator) to supply 1.8V and 3.3V for the rest of the design and a MAX1555 single-cell lithium-ion (Li+) battery charger to charge a Li+ battery. Two MAX40200 (an ideal diode current-switch) are also included to allow either the battery or VBUS from the USB port to supply power. The MAX40200 ideal diode has a forward voltage drop that is an order of magnitude better than a Schottkey diode. The MAX6864 (a nanopower μP supervisory circuit with manual reset and a watchdog timer) is used to monitor the 3.3V supply voltage and reset the microcontroller if it drops below 3.1V. The design also contains an FTDI FT234 USB-to-serial UART interface and a STMicroelectronics® STM32L432KC low-power microcontroller.
Designed, Built, Tested
This document describes the hardware shown above. It provides a detailed systematic technical guide to design in a small-size, low-cost, low-power, high-accuracy heartrate monitor. The design has been built and tested, details of which follow later in this document.