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Do we need an external Reverse Polarity Protection Diode for LITIX™ Basic and Basic+ Designs?

Do we need an external Reverse Polarity Protection Diode for LITIX™ Basic and Basic+ Designs?

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Do we need an external Reverse Polarity Protection Diode for LITIX™ Basic and Basic+ Designs?

LITIX Basic and Basic+ devices are reverse polarity protected:

  • LITIX™ Basic down to -16V
  • LITIX™ Basic+ down to -18V

This means that if we have a static pulse higher than -18V and we don’t have an external reverse polarity diode we could destroy the device.

For transient pulses we recommend a TVS diode ±36V, reverse polarity diode 36V and ceramic capacitor inline with the EMC report:

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Note: The EMC test applies the surge pulse on a single device only. System-level behavior depends on number of components and filters present on the shared supply line. This usually relaxes the stress seen by a single device. Consequently the removal of a reverse diode can be assessed by the customer based on characterization results. 

Another idea is an asymmetrical configuration, with two unidirectional suppressor diodes 15V and 26V and a ceramic capacitor. In this case you won’t need the reverse polarity diode, but an assessment on system-level is required.

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 See the corresponding datasheets at https://www.infineon.com/cms/en/product/power/lighting-ics/litix-automotive-led-driver-ic/litix-basi... .

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