The SM3321A is an image sensor IC that incorporates a single-pixel photodiode and optical detector circuit in an ultra small package. Authentication devices that use light require a general-purpose photodiode and op-amp for each detection wavelength. The SM3321A incorporates the optical detector and amplifier in a single ultra small package.
The integrated optical detector circuit comprises a 0.5mm2 size photodiode and op-amp, which reduces the effects of noise. The gain of the built-in amplifier can be controlled from an external terminal, and the device can detect wavelengths of light from visible light to infrared.
In addition, several SM3321A devices can be connected in parallel to increase the width of detection, allowing it to support a wide range of optical detection systems.