EVALZ-ADPD2212

FEATURES FUNCTIONAL BLOCK DIAGRAM Ultrahigh detectivity photodetector 90 fA/√Hz (typical) ultralow noise floor Signal-to-noise ratio (SNR) near shot noise limit 137 µA (typical) of supply current when active (EE = 0 µW/cm2) 1 µA (typical) of supply current in standby High speed, deep junction photodiode Nominal linear output current: 240 µA (typical) Flexible output configuration Excellent pulse response High ambient light rejection Space-saving, 3 mm × 4 mm LFCSP package VCC + CURRENT AMPLIFIER – OUT ADPD2212 PWDN GND 13721-001 Data Sheet Low Noise, High Sensitivity Optical Sensor ADPD2212 Figure 1. APPLICATIONS Heart rate, pulse oximetry monitoring (photoplethysmography) Battery-powered medical sensors Chemical analysis GENERAL DESCRIPTION The ADPD2212 is an optical sensor optimized for biomedical applications. Very low power consumption and near theoretical signal-to-noise ratio (SNR) are achieved by packaging an ultralow capacitance deep junction silicon photodiode operated in zero bias photoconductive mode with a low noise current amplifier. The ADPD2212 offers a typical 400 kHz bandwidth performance, which is well suited for use with pulsed excitation. The ADPD2212 uses very little power during operation and incorporates a power-down pin, enabling power cycling to optimize battery Rev. 0 life in portable applications. The ADPD2212 provides shot noise limited performance, making it an excellent choice for measuring signals with the highest possible fidelity in low light conditions. This combination of low power, very high SNR, and electromagnetic interference (EMI) immunity enables low power system solutions not possible with traditional photodiode (PD) and transimpedance amplifier (TIA) systems. 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Technical Support www.analog.com ADPD2212 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Shot Noise Limited Performance ................................................9 Applications ....................................................................................... 1 Sensitivity and SNR .......................................................................9 Functional Block Diagram .............................................................. 1 Linearity..........................................................................................9 General Description ......................................................................... 1 Package Considerations ................................................................9 Revision History ............................................................................... 2 EPAD Connection .........................................................................9 Specifications..................................................................................... 3 Applications Information .............................................................. 10 Absolute Maximum Ratings............................................................ 4 Powering the Device .................................................................. 10 Thermal Resistance ...................................................................... 4 Power-Down Mode .................................................................... 10 Soldering Profile ........................................................................... 4 Pulse Mode Operation ............................................................... 10 ESD Caution .................................................................................. 4 Output Configuration ................................................................ 10 Pin Configuration and Function Descriptions ............................. 5 3-Wire Cable Voltage Configuration ....................................... 10 Typical Performance Characteristics ............................................. 6 3-Wire Current Mode Configuration ...................................... 10 Terminology ...................................................................................... 8 Evaluation Board Schematic and Layout .................................... 12 Theory of Operation ........................................................................ 9 Outline Dimensions ....................................................................... 13 Overview........................................................................................ 9 Ordering Guide .......................................................................... 13 REVISION HISTORY 4/16—Revision 0: Initial Version Rev. 0 | Page 2 of 13 Data Sheet ADPD2212 SPECIFICATIONS VCC = 3.3 V, TA = 25°C, λ = 528 nm, unless otherwise noted. IPD is the photodiode current, IMOD is the modulation current, EE is irradiance, IOUT is output current, VBIAS is the bias voltage, RFEEDBACK is the TIA feedback resistor, and RLOAD is the load resistance. Table 1. Parameter GAIN Gain (Current Amplifier) DYNAMIC PERFORMANCE Frequency Response Peaking Rise Time Fall Time Bandwidth OPTICAL PERFORMANCE Diode Active Area Saturation Irradiance NOISE PERFORMANCE Current Noise, Output Referred1 Current Noise Floor, Input Referred Noise Equivalent Power EE Required for SNR = 10000:1 POWER AND SUPPLY Supply Voltage Power Supply Rejection Ratio Current Standby Supply at EE = 0 µW/cm2 Supply2 OUTPUT CHARACTERISTICS Amplifier Static Bias Current Input Referred Output Referred Maximum Output Voltage Nominal Linear Output Current Linearity into TIA Linearity into Resistive Load Peak Output Current3 Output Capacitance Output Resistance POWER-DOWN LOGIC Input Voltage High Level Low Level Leakage Current High Low OPERATING AMBIENT TEMPERATURE RANGE Symbol Test Conditions/Comments Min βTLA tR tF BW NEP VCC PSRR ISTANDBY IFLOOR ISUPPLY 10% to 90% full scale (FS) (IOUT = 24 µA) 90% to 10% FS (IOUT =24 µA) IPD = 10 nA, IMOD = 1 nA EE = 0 µW/cm2 IPD = 10 nA to 300 nA IPD > 300 nA EE = 0 µW/cm2, at 1 kHz At 1 kHz At 1 kHz 1.8 VCC = 1.8 V to 5.0 V, EE = 1600 µW/cm2 PWDN > VIH IOUT = 10 µA IOUT = 240 µA VOUT_MAX IOUT_FS VBIAS = 1.3 V, RFEEDBACK = 25 kΩ IOUT < 100 µA , RLOAD = 5 kΩ From OUT to GND From OUT to GND VIH VIL IIH IIL Max Unit 24 EE = 0 µW/cm2 EE = 0 µW/cm2 COUT ROUT Typ