LMR66430: LMR66430

Harsha K

Part Number: LMR66430

Tool/software:

Hi Team, I am calculating Enable resistor calculation for the LMR66430R5RXBR for the project. but web bench result is differed from my calculation. can you please share the calculation excel file for the same.

Regards,

Harsha

5 months ago

0 Pramanik Patel 5 months ago

TI__Expert 4760 points

Hi,

Please refer to section: 8.2.3.9 External UVLO data sheet to find the values of Resistors.

RENB is chosen in the range of 10 kΩ to 100 kΩ and then RENT can be found accordingly.

Thanks,

Pramanik Patel

0 Harsha K 5 months ago in reply to Pramanik Patel

Prodigy 180 points

Hi, thanks for quick check. Can you help me with an example. and what is the VEN-VOUT and VEN-HYS values to consider. I have calculated for VON 8V. the result obtained is not matching with the Web Bench. please share the RENB and RENT values for the VON =8V and VOFF = 7.5V

Regards,

Harsha

0 Pramanik Patel 5 months ago in reply to Harsha K

TI__Expert 4760 points

Hi,
The calculations done are correct. I think there is a bug in WEBENCH, I will report to the concerned team.

Also please choose a value RENT smaller than 550, so EN PIN gets sufficient minimum value (1.16V).

You may choose RENT = 500 Ohms.

Thanks,

Pramanik Patel

0 Harsha K 5 months ago in reply to Pramanik Patel

Prodigy 180 points

Hi, Thank you for the verification, just wanted to know, per datasheet 0.7V is the VEN-WAKE pin voltage, but you mentioned to have 1.16V. is something I missed from datasheet

Regards,

Harsha

0 Pramanik Patel 5 months ago in reply to Harsha K

TI__Expert 4760 points

Hi,

When EN voltage goes above 0.7, VCC is powered up, but SW node will not switch. It is when it crosses 1.17V the output comes up.

Thus, EN voltage must be above 1.17V to enable output.

Thanks,

Pramanik Patel

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LMR66430: LMR66430