Osram’s photodiode chips for rain sensors
Osram Opto Semiconductors has presented what it claims to be the world’s first surface-mount technology (SMT) package for large-area photodiode chips, which are suited for use in rain sensors. The new SFH 2200 A01 and SFH 2200 FA A01 are mounted behind the vehicle’s windshield. When a raindrop falls on the windshield, the diodes detect a change in the incidence of light. This change is translated by the system to control the windshield wipers and the rate at which they operate. The photodiode chips comply with automotive industry requirements and are approved to operate at temperatures up to 125°C. The photodiodes also meet the requirements for AEC-Q101-C qualification.
The photodiodes feature an improved moisture sensitivity level (MSL) to allow customers more time to solder them on the board. When stored under defined conditions at a temperature of ≤30°C and 60% humidity after the dry packaging has been opened, they can be soldered without damage for up to one year after initial contact with air. Additionally, the broadband diodes are surface mountable, allowing them to be soldered using the reflow method, which makes it easy to check the solder at all the contacts.
“Osram is once again leading the pack with the development of one of the industry’s smallest photodiodes that will reduce manufacturing costs by providing a longer shelf life after opening,” said Rajeev Thakur, Regional Marketing Manager at Osram Opto Semiconductors. “Osram’s innovative design and engineering has led the company to achieve MSL level 2 for the SFH 2200 A01 and the SFH 2200 FA A01. By using encapsulation material containing silicone, we’ve provided a way for moisture and gases to escape more quickly during soldering. The combination of silicone and the stability of the plastic package of the component ensures that the photodiodes are particularly robust.”
The SFH 2200 A01 and SFH 2200 FA A01 feature a footprint of 4.0 mm x 5.1 mm x 0.85 mm—much smaller than the 4.0 mm x 6.5 mm x 1.15 mm of its predecessors, the BPW34S and BPW34FAS. Both units are almost identical, with the only difference that the SFH 2200 FA A01 has a daylight filter.