About internal LDO Equivalent circuit at LM43603?

Bob Lee62837

Other Parts Discussed in Thread: LM43603

Dear support member,

My customer used LM43603.

BIAS used Vout voltage(5V).
Could you teach Equivalent circuit in the of internal LDO at LM43603?
How do behave Internal LDO?

Best regard.

Bob Lee.

over 9 years ago

0 Frank De Stasi over 9 years ago

TI__Guru 72415 points

The internal VCC is an LDO that powers most of the circuit inside the device. The VCC pin is the output of the LDO. The input of the LDO comes from either the VIN or BIAS pins. If the voltage on the BIAS input is less than about 3.3V, the input to the LDO is switched to VIN. If the voltage on the BIAS pin is more than about 3.3V the input to the LDO is switched to the BIAS input.

0 Bob Lee62837 over 9 years ago in reply to Frank De Stasi

Mastermind 7230 points

Dear Frank De Stasi,

Thank you very much for reply.

May I ask add a question?

BIAS use Vout voltage.

If there is not bypass capacitor(1uF~10uF) in BIAS pin,
internal LDO will not work?

Best regard.

Bob Lee.

0 Frank De Stasi over 9 years ago in reply to Bob Lee62837

TI__Guru 72415 points

It is best practice to have a small capacitor connected from the BIAS input to ground, near the device.

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About internal LDO Equivalent circuit at LM43603?