ADI's ADPD188BI is a photometric system using optical dual wavelength technology. The module integrates a highly efficient photometric front end, two light emitting diodes (LEDs), and two photodiodes (PDs). These items are housed in a custom package that prevents light from going directly from the LED to the PD without first entering the smoke detection chamber.

The ADPD188GG was designed to measure optical signals from ambient light and synchronous reflected LED pulses. Synchronous measurement offers best-in-class rejection of ambient light interference, both DC and AC. The module integrates a highly efficient photometric front end, two LEDs, and two PDs. All these items are housed in a custom package that prevents light from going directly from the LED to the PD without first entering the subject.

The front end of the application specific integrated circuit (ASIC) consists of a control block, a 14-bit analog-to-digital converter (ADC) with a 20-bit burst accumulator, and three flexible, independently configurable LED drivers. The control circuitry includes flexible LED signaling and synchronous detection. The analog front end (AFE) features best-in-class rejection of signal offset and corruption due to modulated interference commonly caused by ambient light. The data output and functional configuration occur over a 1.8 V I²C interface or serial peripheral interface (SPI) port. The ADPD188BI was specifically designed for smoke detector applications, and the ADPD188GG was designed for optical heart rate monitors and reflective SpO₂ measurement applications.