Jeremy Hochschwender, a three year veteran here at the University of New Hampshire InterOperability Laboratory (UNH-IOL) recently sat down with me to discuss his job of designing printed circuit boards, or PCBs, here at the lab. The PCBs that Jeremy designs are used in MIPI DPHY testing. MIPI DPHY is a standard that defines communication specifications as well as the required electrical characteristics for cell phone components such as the display or the camera sensor. The MIPI Consortium uses these boards for testing, and also sells them to companies to use for in-house testing as an alternative to sending the devices to the UNH-IOL or other labs for testing. Giving companies the freedom to conduct the testing on their own allows them to identify potential problems themselves, saving time and money in the end.
Jeremy’s work in the MIPI Consortium deals specifically with the electronic signals that are transmitted between the camera on a phone, and the processor in the phone. Jeremy is able to use MIPI test fixtures to do things such as verify that a camera meets the standards set by the specification. In order to test this, Jeremy uses an evaluation board with a camera sample, and connects this evaluation board to the MIPI DPHY RTB. The RTB will simulate the signal reflections that would occur were the camera sensor actually hooked up to a phone. He is then able to monitor the traffic coming from the evaluation board and assess that the camera sensor is properly transmitting data.
The design process for these boards is not simple. There are many steps in the board design process. It is a repeating cycle of developing, manufacturing, and testing. The reason that these circuit boards take so long to complete is because of the quality work that goes into making the product and the attention to the strict guidelines and standards that Jeremy must follow while building each fixture. Each test fixture must follow a certain set of standards set by the MIPI Alliance. The boards are designed for testing and as such, the results are affected by the electrical characteristics of the PCB. These test fixtures are used with very high speed signaling, and as such very small things can cause big problems. Trace lengths must be matched to ensure that problems such as clock to data skew are diminished. Likewise one must be aware of how the amount of solder will affect the impedance of the boards at such high frequencies. The design process is also open ended in its nature. Specifications are constantly updated, speeds increase, and changes must be made to ensure that customers are receiving the highest quality product.
While the MIPI Consortium designs and sells these boards for commercial use, the Ethernets consortia use these circuit boards for internal purposes. These boards are useful in creating test setups for the Ethernet consortia to verify PHY level conformance of commercial products.
The circuit boards built and developed by Jeremy are just one of many test tools offered here at the UNH-IOL that work to create cost effective solutions for its members. The test services offered at the UNH-IOL are one of a kind and valued across many industries. Whether it’s Ethernets, MIPI or IP, each consortium is staffed with talented students who are gaining knowledge of the industry and earning countless opportunities to apply what they know to the real world through these testing services.
To find out more about the boards or to order visit our website here: https://www.iol.unh.edu/solutions/test-tools/mipi-boards