LPC55S6x - LPC55S66JBD100K

[hemalatha_r]

Hi NXP team,

As per datasheet page 37 VDD_PMU is tied to FB pin when using internal DC DC Conveter do we have to connect capacitors to it ? Like in EVK LPCXpresso55S69 ?

[soledad]

Hi, 

Yes, the capacitor is needed because the DCDC requires at least one cap to have enough power feedback.

Have a great day,
Sol

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[cmkessell]

Is there any further guidance as to how to use the LPC55S69's DC-DC converter (aside from just copying the EVK design) and the recommended component values to attach to the VDD_PMU, FB and LX pins?  The data sheet and user manual don't reveal much.

For example the EVK design has 4 decoupling capacitors attached to the FB-to-VDD_PMU connection - are they all necessary?