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LTC3605 - Bootstrapping diode

Category: Hardware
Product Number: LTC3605

Hi,

We need some clarification regarding the LTC3605.

Datasheet does not state clearly if the bootstrapping diode is included in the package or an external diode is always required. All the design guidelines include an external bootstrap diode, but the block diagram in the datasheet include a diode and it is not clear if it is inside the package or outside.

Effectively if there's a diode inside, placing another diode outside in parallel would be unnecessary specially without knowing the Vforward of the inside diode.

From the block diagram:

  • Is Db included inside the LTC3605? or it is absolutely required to have an external diode for the bootstrapping circuit to work properly?
  • From the simulation file, I can see that removing the Diode does not affect the Buck functioning, but my understanding is that without that diode the Buck shouldn't be able to raise the NMOS gate voltage above PVIN when it is in conduction. What could be the result of not having this diode?

Thanks

Parents
  • FormerMember
    0 FormerMember

Hello,

See highlights below. These are the pins. Beyond the pins are external components. This diode is external, not internal.

Regards,

Jhun

Reply
  • FormerMember
    0 FormerMember

Hello,

See highlights below. These are the pins. Beyond the pins are external components. This diode is external, not internal.

Regards,

Jhun

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