The 2SD1664T100R is a Bipolar Transistor (BJT) manufactured by ROHM with an NPN type configuration. It has a voltage rating of 32V and a current rating of 1A. The transistor is designed to provide low power amplification, switching and signal processing. It is suited for a variety of applications, such as motor control, drive systems, and security systems. The 2SD1664T100R has a wide variety of features that provide superior performance, including high-speed switching and excellent thermal stability. It also offers improved temperature and voltage protection, improved EMI suppression, and improved high-frequency characteristics.