Automotive-grade high-voltage rectifiers

Paul Boughton

The latest series of high-voltage rectifiers introduced by Diodes Incorporated features two AEC-Q101-qualified devices designed to provide robust rectification, blocking, and reverse-battery protection for automotive electronic control units (ECUs). The compact, small form factor and thermally efficient SOD123F package enables the S1MSWFQ standard rectifier and RS1MSWFQ fast rectifier to deliver a superior level of performance from a PCB footprint that is less than half that of similar SMA packaged rectifiers.

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).