PIN Photodiode TO-39 Package. This BPX 61, from OSRAM Opto Semiconductors, is a silicon PIN photodiode in a hermetically sealed TO-39 package. It is designed for applications with a wavelength of 400 to 1100 nm. Suitable applications for the BPX 61 photodiode include; industrial electronics, photointerrupters, IR remote control and for control/drive circuits.. Features of the BPX 61 photodiode: TO-39 package (similar to TO-5) Hermetically sealed metal can Suitable for applications up to 125°C Short switching time