LM5069: dv/dt circuit design question

Ann_Lien

Part Number: LM5069

Hi expert,

My customer is using dv/dt circuit like below picutre in LM5069. Would you kindly help to suggest how to design the BJT here? As I know, we can pick voltage rating over 2*Vg. But I didn't know how to pick current rating for it. Could you kindly help on this case? Thanks a lot!!

Best regards,

Ann Lien

over 6 years ago

0 Rakesh over 6 years ago

TI__Guru** 104931 points

Hi Ann Lien,

I will get back to you soon.

Regards,
Rakesh

0 Rakesh over 6 years ago in reply to Rakesh

TI__Guru** 104931 points

Hi Ann Lien,

We usually select BJT which can support continuous current of 0.5A to 1A. Though the transient discharge current from the Cdvdt capacitor would be much higher but we have never faced any issue as it is for very short interval <10us.

General recommendation is MMBT5401LT1G

Regards,
Rakesh

0 Ann_Lien over 6 years ago in reply to Rakesh

TI__Genius 12620 points

Hi Rakesh,

Thanks for your reply!! Will update to customer, thanks a lot!!

Best regards,

Ann Lien

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LM5069: dv/dt circuit design question