Photometric Front End with One Input and SPI

The ADPD105/ADPD106/ADPD107 are highly efficient, photometric front ends, each with an integrated 14-bit analogto-digital converter (ADC) and a 20-bit burst accumulator that works with flexible light emitting diode (LED) drivers. The accumulator is designed to stimulate an LED and measure the corresponding optical return signal. The data output and functional configuration occur over a 1.8 V I2C interface on the ADPD105 or SPI on the ADPD106 and ADPD107. 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.

Couple the ADPD105/ADPD106/ADPD107 with a low capacitance photodiode of <100 pF for optimal performance. The ADPD105/ADPD106/ADPD107 can be used with any LED. The ADPD105 is available in a 2.46 mm × 1.4 mm WLCSP and a 4 mm × 4 mm LFCSP. The SPI only versions, ADPD106 and ADPD107, are available in a 2.46 mm × 1.4 mm WLCSP.

Applications

* Wearable health and fitness monitors

* Clinical measurements, for example, SpO2

* Industrial monitoring

* Background light measurements

* Multifunction photometric front end

* Fully integrated AFE, ADC, LED drivers, and timing core

* Enables best-in-class ambient light rejection capability without the need for photodiode optical filters

* Three 370 mA LED drivers

* Flexible, multiple, short LED pulses per optical sample