Space-saving HV rectifiers protect automotive ECUs

November 19, 2015 // By Christoph Hammerschmidt
A series of high-voltage rectifiers from Diodes, Inc. can provide robust protection for sensitive electronic control units in cars. The S1MSWFQ standard rectifier and the faster RS1MSWFQ offer rectification, blocking, and reverse-battery protection for automotive electronic control units (ECUs) - all in the small and thermally efficient SODF123F package.

With a maximum off-board profile of 1.15mm, the SOD123F is less than half the height of the SMA package, while its board footprint of 7mm2 occupies just 43% of the area required by the equivalent SMA part. In addition to providing circuit designers with space-saving benefits, the SOD123F package offers superior thermal performance with a junction-to-case thermal resistance of 13°C/W compared to the SMA package’s 30°C/W rating, using recommended pad layouts.

With a minimum reverse-breakdown voltage of 1000V these rectifiers ensure plenty of voltage headroom for automotive system designs. This allows for voltage spikes caused by inductive kickback from coils and inductors and means these devices will meet ISO7637 in withstanding electrical disturbances when used for ECU reverse-battery protection. The performance features of the S1MSWFQ and RS1MSWFQ rectifiers all contribute to the robust and reliable operation demanded by harsh automotive environments. This is further underwritten by AEC-Q101 qualification of these devices and supported by the automotive industry’s Production Part Approval Process (PPAP).

Offered in small form-factor, thermally efficient flat-lead SOD123F packages, the S1MSWFQ-7 is priced at $0.057 in 3000 unit tape & reel quantities while the 240ns fast-recovery RS1MSWFQ-7 is priced at $0.069, also in 3000 unit tape & reel quantities.

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