The OB1203 is a fully integrated optical sensing module for Pulse Oximetry (PPG - photoplethysmography), multi-channel Color Sensing (CS), Ambient Light Sensing (LS) and Proximity Sensing (PS).

With the appropriate algorithm, it can determine human heart rate, blood oxygen saturation (SpO2), respiration rate and heart rate variability (a measure of stress). The OB1203 integrates all light sources, drivers, and the sensor elements, in a single optically optimized package.

A major application of the device is consumer and mobile devices, enabling biosensing features and display control in a single device. The OB1203 can determine proximity of nearby objects in order to support the deactivation of touch screen displays or the detection of a finger for pulse oximetry measurements, for example. The sensor combines optical sensing features (CS, LS, PS) and bio-sensing functionality (PPG) without the need for a transparent optical opening. The unique implementation of OB1203 enables SpO2 measurements behind IR transmissive ink, making the device virtually invisible, and allowing for aesthetic industrial designs.


  • Biosensor:
    • SpO2 measurement behind IR transmissive, but visibly dark ink
    • Industry’s smallest package: 4.2mm × 2mm × 1.2mm
    • Fully integrated and trimmed module including two LEDs, 250mA max drive current and photodetectors 
    • High SNR and Crosstalk cancelation (analog and digital)
  • Ambient Light / Color Sensor:
    • High illuminance accuracy across various light sources
    • Absolute sensitivity: 0.06 lx to > 150,000 lx
    • Output resolution LS/CS: 13 to 20 bits
    • Four LS/CS gain modes: x1 to x6
    • Highly linear output, 50Hz/60Hz light and fluorescent light flicker immunity
  • Proximity Sensor:
    • Integrated and trimmed LED source, driver (250mA) and photodetector
    • High resolution (12 to 16 bits)
    • Object movement detection (in/out)
    • Ambient light suppression > 100 klx sun light




Design & Development

Software & Tools

Software Downloads

Type Title Date
Software & Tools - Evaluation Software Log in to Download ZIP 4.87 MB
Software & Tools - Other
2 items

Sample Code

Boards & Kits

Boards & Kits


Bio and Light Sensor Module

A brief introduction to Renesas' biosensor module for heart rate, SpO2 and respiration using the highly integrated OB1203 for reflective photoplethysmography, light and color sensing. With the provided algorithm, the solution can determine heart rate, oxygen saturation (SpO2) and respiration rate. The sensor transmits its data via an I2C interface to an MCU for data analysis and result display. The evaluation kit also incorporates an RL78/G13 16-bit microcontroller, an ISL9111 high-efficiency synchronous boost converter for battery operation and an OLED display.