SDP8406-002

The SDP8406-002 is a phototransistor optical sensor based on a monolithic integrated circuit designed for autosensing applications. The device consists of a photodiode, a PNP bipolar transistor, and integrated circuit components that perform a high-gain, monolithic, transimpedance amplifier. Designed with both photodiode and circuitry optimized for DC/AC applications, the SDP8406-002 allows wide flexibility for fast detection and response to light stimuli. The output circuit is designed to be an open collector, enabling the user to connect the device to an external load and sample at any desired level.

The core of the SDP8406-002 is a Light-to-Current Photo Transistor with an adjustable gain amplifier (switchable between 1000 and 3000). This integrated circuit has a phototransistor with an NPN-PNP amplifier in a single package. The IC features two pairs of Field Effect Transistors (FETs) arranged in series like a differential amplifier configuration and connected to each other’s drains, containing noise cancellation circuitry. The amplifier arrangement provides a complete feedback loop around the phototransistor, enabling high conversion gain and low noise performance.

The SDP8406-002 has two pins indicating the direction of the current flow, enabling direct current for the output measurement. The photodiode is capped with a glass lens, enabling a direct current of up to 10mA to be transmitted from the positive pin to the negative pin. These two pins also enable the use of AC current for the output measurement.

The SDP8406-002 achieves a high conversion gain (20000-30000) and enables a wide range of sensitivity adjustment via its adjustable gain circuit. This feature makes the device suitable for a wide variety of applications, including automotive applications, home appliances, alarm systems, material sorting and more.

The adjustable gain amplifier circuit is what makes the SDP8406-002 unique. It simplifies the process of obtaining a desired output. Additionally, the circuit contains noise cancelling circuitry, which eliminates low frequency noise and is also responsible for providing a high common-mode rejection ratio up to 70dB. Motors, switching power supplies, and other electrical sensors often produce noise that can interfere with the readings. The adjustable gain amplifier works to reduce or eliminate these unwanted signals, enabling accurate readings from the optical sensor.

The SDP8406-002 is a versatile optical sensor and has a wide range of applications including photometric, metrology, illumination level sensing, tracking objects, and more. Its current output makes it an ideal choice for systems that require a precise current output. The adjustable gain circuit ensures accurate readings despite the presence of electrical noise. Moreover, its low power consumption and small size make it a good fit for applications with restricted space constraints or budget.