Low Noise, High Sensitivity Optical Sensor
Data Sheet
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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
(E
E
= 0 µW/cm
2
)
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
APPLICATIONS
Heart rate, pulse oximetry monitoring
(photoplethysmography)
Battery-powered medical sensors
Chemical analysis
FUNCTIONAL BLOCK DIAGRAM
Figure 1.
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
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.
13721-001
GND
PWDN
OUT
ADPD2212
VCC
CURRENT
AMPLIFIER
+
–
