ADPD175GGI-ACEZRL7

Integrated Optical Module with Ambient Light Rejection and Three LEDs ADPD175GGI Data Sheet GENERAL DESCRIPTION 2.8 mm × 6.5 mm module with integrated optical components 2 green LEDs located on either side of the photodiode, 1 infrared LED, and 1 photodiode True 3-channel 370 mA LED driver Separate LED and AFE settings for each channel Dual data registers for each LED return signal 14-bit ADC 20-bit burst accumulator enabling 20 bits per sample period On-board sample to sample accumulator enabling up to 27 bits per data read Custom optical package designed to operate under a glass window Optimized signal-to-noise ratio (SNR) for signal limited cases The ADPD175GGI is a complete photometric system designed to measure optical signals from ambient light and from synchronous reflected LED pulses. Synchronous measurement offers best-inclass rejection of ambient light interference, both dc and ac. The module integrates a highly efficient photometric front end, three LEDs, and a photodiode (PD). All these items are housed in a custom package that prevents light from moving directly from the LED to the photodiode without first entering the subject. TE FEATURES 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. Optical heart rate monitoring (HRM) Reflective SpO2 measurement LE APPLICATIONS FUNCTIONAL BLOCK DIAGRAM VDD1 ADPD175GGI VDD2 B SO ANALOG BLOCK PHOTODIODE 1 TIA BPF ±1 INTEGRATOR VBIAS TIA DPST PHOTODIODE 2 BPF ±1 INTEGRATOR AGND VBIAS VREF LEDs VLED2 TIA BPF IR VBIAS O VLED1 GREEN LED3/DNC LED2 LED1/DNC TIA BPF 1µF TIME SLOT A DATA ±1 INTEGRATOR 14-BIT AD C ±1 INTEGRATOR AFE CONFIGURATION, TIME SLOT A AFE CONFIGURATION, TIME SLOT B VBIAS AFE: SIGNAL CONDITIONING LED3 DRIVER LED2 DRIVER LED3 LEVEL AND TIMING CONTROL LED1 DRIVER LED2 LEVEL AND TIMING CONTROL TIME SLOT A DATA SDA SCL INT DGND DIGITAL INTERFACE AND CONTROL LED1 LEVEL AND TIMING CONTROL 13017-001 LGND NOTES 1. DNC = DO NOT CONNECT. DO NOT CONNECT TO THIS PIN WHEN USING INTERNAL LEDs. Figure 1. For more information about the ADPD175GGI, contact Analog Devices, Inc., at optical_sensors@analog.com. Rev. SpA Document Feedback Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781.329.4700 ©2016–2017 Analog Devices, Inc. All rights reserved. Technical Support www.analog.com ADPD175GGI Data Sheet O B SO LE TE NOTES I2C refers to a communications protocol originally developed by Philips Semiconductors (now NXP Semiconductors). ©2016–2017 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D14941F-0-4/17(SpA) Rev. SpA | Page 2 of 2