SDP8436 Series Silicon Phototransistor, Side-looking Black Plastic Package. The SDP8436 is an NPN silicon phototransistor molded in a black plastic package which combines the mounting advantages of a side-looking package with the narrow acceptance angle and high optical gain of a T-1 package. The SDP8436 is designed for those applications which require longer coupling distances than standard side-looking devices can provide, such as touch screens. The device is also well suited to applications in which adjacent channel crosstalk could be a problem. The package is highly transmissive to the IR source energy while it provides effective shielding against visible ambient light.