TPSM84824: Resistor Tolerance

Mark Philip Felipe

Part Number: TPSM84824
Other Parts Discussed in Thread: TPS54824

Hi Team, We would like to seek your support. On page 19 of the datasheet, under Sequencing, there are computations of R1 and R2. Do we have a tolerance set for those resistors?

Thank you.

Regards,

Mark

over 3 years ago

0 Gerold Dhanabalan - Online Design Tools over 3 years ago

TI__Genius 14455 points

Hi Mark,

You should be good using 1% tolerance resistors for the equations given in page 19 of the datasheet.

Regards,

Gerold

0 Mark Philip Felipe over 3 years ago in reply to Gerold Dhanabalan - Online Design Tools

TI__Genius 9705 points

Hi Gerold, May we know if there is a significant impact using 5% to 10% tolerance? Thanks!

-Mark

0 Gerold Dhanabalan - Online Design Tools over 3 years ago in reply to Mark Philip Felipe

TI__Genius 14455 points

Hi Mark,

Yes, you could . You have to check such that the voltage at the TRACK pin with the resistor divider tolerances are above 0.9V. As long as you can take care of this, you should be good. For a 10% tolerance case,

Vtrack = Vout_primary * (1 / (1 + Rtop/Rbottom))

Worst case is Rtop = +10% of Rtop_nominal

Rbottom = -10% of Rtop_nominal

Calculate your Vtrack with these and check if it is above 0.9V.

Please refer to figure 14 of the TPS54824 (the converter) datasheet to refer to where I am picking the 0.9V number from.

regards,

Gerold

0 Mark Philip Felipe over 3 years ago in reply to Gerold Dhanabalan - Online Design Tools

TI__Genius 9705 points

Hi Gerold, Vout is the Vout1 on the schematic, is that correct?

Thanks!

-Mark

0 Gerold Dhanabalan - Online Design Tools over 3 years ago in reply to Mark Philip Felipe

TI__Genius 14455 points

Hi Mark,

Yes, Vout_primary is the Vout1 in Figure 27 of the datasheet.

regards,

Gerold

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TPSM84824: Resistor Tolerance