LM5109B: How to treat unused pin (HI, HB, HO. HS)

Taito Takemura

Part Number: LM5109
Other Parts Discussed in Thread: , UCC44273

HI team,

The customer is considering using LM5109BSD/NOPB. They are using it as a level shifter from 3.3V to 10V using only the low side gate driver. They will use only the red square in the figure below.
Could you please tell me how to handle empty pins (HI, HB, HO, HS)?

VDD　10V,　LI　3.3V

Regards,

Taito Takemura

over 1 year ago

0 William Moore over 1 year ago

TI__Genius 13655 points

Hey Taito,

Thank you for your question regarding the LM5109B.

Please be aware that the LM5109BSD/NOPB is an OPN for the LM5109B GPN. The LM5109 is an older version of the product that is now listed as Last Time Buy (LTB). For an up to date information on the product, please refer to the LM5109B product page.

It would be best not to leave the empty pins floating. They should be connected to VSS.

Also, we have a large selection of low-side only gate drivers that may work here such as the UCC44273.

Let me know if you have any questions.

Thank you,

William Moore

0 Taito Takemura over 1 year ago in reply to William Moore

TI__Intellectual 2990 points

Hi William,

Thank you for your answer.

Just to be sure, is it okay to connect the LM5109B's power pin HB to VSS as well?

Regards,

Taito Takemura

+1 William Moore over 1 year ago in reply to Taito Takemura

TI__Genius 13655 points

Hey Taito,

Yes, that is okay as long as you do not connect a bootstrap diode to HB from VDD.

Thank you,

William Moore

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LM5109B: How to treat unused pin (HI, HB, HO. HS)