Low Noise, High Sensitivity Optical Sensor

Data Sheet

ADPD2214

Rev. 0

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FEATURES

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

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, 4 mm × 4 mm LFCSP package

APPLICATIONS

Heart rate, pulse oximetry monitoring

(photoplethysmography)

Battery-powered medical sensors

Chemical analysis

FUNCTIONAL BLOCK DIAGRAM

Figure 1.

GENERAL DESCRIPTION

The ADPD2214 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 ADPD2214 offers a typical 75 kHz bandwidth performance,

which is well suited for use with pulsed excitation. The ADPD2214

uses very little power during operation and incorporates a

power-down pin, enabling power cycling to optimize battery

life in portable applications. The ADPD2214 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.

GND

PWDN

OUT

ADPD2214

VCC

CURRENT

AMPLIFIER

+

–