Vishay TEPT4400 Phototransistor Ambient Light Sensor

The Vishay TEPT4400 is a phototransistor ambient light sensor with peak spectral sensitivity at 570 nm, housed in a compact industry-standard T-1 package.

Overview

The Vishay TEPT4400 is a leaded silicon NPN epitaxial planar phototransistor designed to replicate the sensitivity of the human eye. It is tuned to the visible spectrum and serves as a modern replacement for older cadmium sulphide (CdS) photoresistors.

Applications

A key application for this sensor is automatic backlight dimming control. It is used to adjust the brightness of LCD displays and keypad backlights in mobile devices, which helps conserve battery life and improve user comfort. In industrial settings, it can be used for automated on/off lighting operations, contributing to energy efficiency and smart system control.

Key Features

• High photo sensitivity
• Peak spectral sensitivity: 570 nm
• Viewing angle: 60° total (±30° half sensitivity)
• Operating temperature range: -40°C to +85°C
• Power dissipation: 100 mW
• Package: Industry-standard T-1 (3 mm) case style
• Configuration: Simple 2-pin design

The sensor combines high photo sensitivity with a generous viewing angle, and its 2-pin design supports straightforward integration. Its 100 mW power dissipation rating makes it an efficient choice for low-power electronic designs, while its temperature range suits demanding environments. This Vishay phototransistor is a practical component for designers and engineers working in consumer electronics.