Polymer capacitors empower Raspberry Pi 4 microcomputer
Two polymer capacitors from Panasonic Industry Europe replace the multi-layer ceramic capacitors that were previously used in the Raspberry Pi microcomputer.
The Raspberry Pi 4 microcomputer promotes teaching of basic computer science in schools and in developing countries. It features Panasonic Industry Europe’s Polymer SP capacitor. Its low-cost power supply is equipped with Polymer OSCON capacitors from Panasonic Industry Europe.
The Raspberry Pi Foundation replaced two 1206 MLCCs with a single Polymer SP capacitor. The capacitor is compact, with a housing that measures just 7.3 x 4.3 x 1.9mm and has a capacitance value of 100µF and ESR characteristics as low as 15mOhm maximum. According to Panasonic Industry Europe, the SP capacitor helped optimise the design processes as well as the capabilities of the Raspberry Pi 4. The company explained that MLCCs cannot achieve the same high capacitance as polymer for the same given footprint and volume. An MLCC also exhibits strong capacitance dependence on DC bias due to ferroelectric dielectric materials used. The capacitance of these devices varies with applied DC voltage which can lead to a capacity drop of more than 70 per cent, compared to the given specs on the data sheet. Polymer capacitors’ capacitance does not vary significantly when the application voltage changes, reports Panasonic. These characteristics allow a lower part count using SP-Cap with better capacitance range and temperature profile instead of MLCCs. In addition to saving space, the SP-Cap saved space for Raspberry Pi 4 model and also saved costs on parts and reduced the production steps.
The power supply for the Raspberry Pi 4 uses two Panasonic Industry Europe OSCON polymer capacitors with a rated voltage of 6.3V DC. It exhibits long-life characteristics, efficiency and reliability via what is claimed to be the industry’s highest ripple current capabilities (5600mA rms) for a capacitor.
Operating temperature ranges from -55 to +105 degrees C. The capacitor can withstand harsh environments for up to 5,000 hours.