TPS43340-Q1: Using VREG to drive EN3- Data sheet says not to drive external loads, but EVM uses it for this purpose.

UA&A_CodyDowling

Part Number: TPS43340-Q1

TI Team,

The data sheet says this in the pin description section: "...This pin has current limit-protection; do not use it to drive any other loads." However, the EVM (snippet below)shows that the pin can be used to drive EN3 through a 10k resistor:

The EN3 pin current looks to be 0.5uA, and the current limit several hundred milliamps, so maybe that's why it can be used in this way? Is it permissible for us to use it in this way for our design?

Thanks in advance for your help!

Cody

over 5 years ago

0 Kevin LaRosa over 5 years ago

TI__Genius 17380 points

Hi Cody,

You are correct, the warning against loading is generally referring to things in the mA range. Simple pull-ups are very low current and no dynamic loading. That said, you should still have care when routing to ensure that it isn't routed near switching noise. Any noise picked up on this would propagate to the rest of the chip.

0 Mahmoud Harmouch over 5 years ago in reply to Kevin LaRosa

TI__Mastermind 28340 points

Hello,

I would like to add that Vreg is supplying the drivers for the external power FETs and subject to ripple due to gate current demand at switching transition. The ripple is low due to the decoupling cap at Vreg pin. This ripple would not affect logic level but it induces noise to analog circuit supplied by Vreg.

Regards

0 UA&A_CodyDowling over 5 years ago in reply to Mahmoud Harmouch

Expert 1006 points

Thanks for your help Mahmoud, Kevin,

This answers my question. Please feel free to close the ticket.

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TPS43340-Q1: Using VREG to drive EN3- Data sheet says not to drive external loads, but EVM uses it for this purpose.