LM66200: EN sequence require

Jim Tsai

Expert 4470 points

Part Number: LM66200

Hi,

Does the device have Enable signal sequence requirement?

Can I provide EN signal low before input voltage (VIN1 and VIN2) come?

ST pin can be open if I don't use the function, right?

over 3 years ago

0 Elizabeth Higgins over 3 years ago

TI__Genius 16145 points

Hi Jim,

You can leave the ST pin floating as it is an open-drain pin, however this would be sacrificing the ability to see what source is selected and whether a fault condition is occurring.

I will have to look into whether power sequencing outside of the Vin->VEN sequence would cause harm long term to the device.

I will get back to you tomorrow by EOD.

Best Regards,

Elizabeth

0 Jim Tsai over 3 years ago in reply to Elizabeth Higgins

TI__Expert 4470 points

Hi Higgins,

Soft reminder.

0 Jim Tsai over 3 years ago in reply to Jim Tsai

TI__Expert 4470 points

Hi Higgins,

Please also help to review the circuit is ok or not? Feel free provide your comment, thanks.

Please be noted pin4 tie to GND directly.

0 Jim Tsai over 3 years ago in reply to Jim Tsai

TI__Expert 4470 points

Hi Higgins,

Reminder, please help to check above and customer is pushing for this, thanks for the support.

0 Elizabeth Higgins over 3 years ago in reply to Jim Tsai

TI__Genius 16145 points

Hi Jim,

I am very sorry this slipped by while I was out of office.

I will actually have a response for you by the end of the day.

Best Regards,

Elizabeth

0 Elizabeth Higgins over 3 years ago in reply to Elizabeth Higgins

TI__Genius 16145 points

Hi Jim,

There should be no issue having the device active while VIN1 and VIN2 are disconnected because no power will pass through until VIN1/VIN2 exceeds 1.6V. Until this point the device output will be HiZ.

Best Regards,

Elizabeth

0 Elizabeth Higgins over 3 years ago in reply to Elizabeth Higgins

TI__Genius 16145 points

With regard to your schematic, it looks great!

One recommendation is a smaller ST pullup resistance would mean less power dissipation loss as the ST pin will draw a small amount of current (0.03uA max). We typically recommend a 10kohm pullup, but this is completely up to you and the power loss would be very minimal.

Best Regards,

Elizabeth

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LM66200: EN sequence require