AN3361

Conclusion

Doc ID 018589 Rev 1

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Conclusion

Protecting automotive electronic modules from polarity inversion due to poor battery

handling and load-dump surge during battery disconnection while the alternator is still

charging usually involves the use of diodes, especially Schottky diodes rather than bipolar

ones because of their better performance in direct conduction. The choice must consider

the worst-case surge conditions of ISO 7637-2 which are pulses 1 and 5b.

Usually Schottky diodes with a breakdown voltage of 150 V are preferred for this application.

This article shows that a breakdown voltage of 100 V may be selected to withstand

avalanche mode during the negative pulse 1 test (starting from a 2 A Schottky type). This

results in the saving of power during direct conduction.

Note:

ST parts numbers listed in this application note were given as examples and are not an

exhaustive list. Please contact your sales or marketing representative for more automotive

grade rectifier devices.