Low side switch to drive 5V automotive relays

[lajitha]

Hello ST Team,

       We are currently desiging an ECU, which require DO that can drive external 5V automotive relays. We have identified L9338(AEC-Qualified part)  from ST for our design. Kindly confirm its selection and longevity of the part. 

Thanks & Regards

Lajitha

[Peter BENSCH · Accepted solution]

There are many low-side switches in the portfolio of STMicroelectronics, but since you have not mentioned any requirements other than the voltage of 5V and automotive, nobody can make a more detailed statement.

Regarding long-term availability, the L9338 is not guaranteed for product longevity. Future availability depends on worldwide demand. However, your preferred distributor will warn you in good time of any imminent discontinuation so that you can buy and keep sufficient stock. However, no discontinuation is currently foreseeable.

Hope that answers your question?

Regards
/Peter

[lajitha]

Hello Peter,

     Thanks for your reply. Let me explain in detail: we require 150mA /5V Digital output signal from our ECU to drive external 5V automotive relay. We are planning that, our current  ECU design shall have a life span of of 15 years. Please suggest suitable automotive grade low side switches that meets our requirement. 

One more point to add here, that our ECU design shall be compliant to the ISO 7637-3 transients and ISO 10605 ESD standards.

Thanks & Regards

Lajitha

[lajitha]

Hello  Peter BENSCH,

  Could you please provide comments on my queries.

Thanks & Regards

Lajitha

[Peter BENSCH]

Many automotive devices are guaranteed to have a product longevity of 15 years from market launch, but this is not yet the case for any low-side drivers. For more detailed information, please contact your local distributor or ST sales office.

Transient immunity is achieved with additional protective circuitry, e.g. using TVS.

Good luck!
/Peter

[lajitha]

Hello Peter,

  We have selected the L9338 part for driving external 5V automotive relay in our ECU design. We have provided ESDA6V1LY device as protection against ISO 7637-3 fast and slow transients and ISO 10605 ESD. Please review the schematic circuit we have designed using the L9338 for our use case and provide your valuable comments.

If you can suggest some similar parts , it will be very useful.

Thanks & Regards

Lajitha

[Peter BENSCH]

I can only review your schematics for device L9338, as I am not familiar with your system or cabling, nor your layout or sources for possible transients. As far as the L9338 is concerned, I would set IN4 to a fixed potential, i.e. to H when PRG=L and the output should be switched off.

Regards
/Peter