The new Raspberry Pi 4 is a microcomputer that promotes the teaching of basic computer science in schools and in developing countries. It highlights Panasonic Industry Europe’s Polymer SP capacitor substituting the previously used MLCC’s. Additionally, the newly developed low-cost power supply of the Pi 4 is furnished with Polymer OSCON capacitors from the company, giving a reliable, high-tech and cost-efficient solution for end-users.
The Raspberry Pi Foundation replaced two 1206 MLCCs with just one of Panasonic’s Polymer SP capacitors that provides to the performance and reliability of this powerful Raspberry Pi microcomputer. With a compact housing of only 7.3mm x 4.3mm x 1.9mm and a capacitance value of 100µF as well as low ESR characteristics (15mOhm max.), the capacitor assisted in optimising the design processes as well as the abilities of the Pi 4. MLCCs are unable to achieve the same high capacitance as a polymer for the same given footprint and volume. Also, the MLCC presents strong capacitance dependence on DC bias due to ferroelectric dielectric materials used for MLCCs. The capacitance of these devices diversifies with applied DC voltage which can lead to a capacity drop of more than 70% in comparison to the given specs on the data sheet.
For polymer capacitors, the capacitance does not vary a great deal when the application voltage changes. These advantages enabled a lower part count using SP-CAP with a better capacitance range and temperature profile instead of MLCCs for the Pi 4 model, which not only preserved space on the PCB but also saved costs on parts and reduced the production steps.