TPS791: Tolerance of Vref

Danilo A.

Mastermind 24715 points

Part Number: TPS791

Hi Team,

The reference voltage value of TPS79101 is 1.2246V, What is the tolerance?

Regards,

Danilo

over 3 years ago

0 Kyle Van Renterghem over 3 years ago

TI__Genius 13085 points

Hi Danilo,

The reference isn't specified directly since it is not accessible to the user. Instead we specify that output voltage will be within +-2% across line, load and temp since this is what the user actually sees in their application. Also keep in mind that any error introduced by your resistor divider will be added to that +-2%.

I've provided a quick image capture of the EC table showing the relevant spec, which is proportional to Vout (0.98*Vout to 1.02*Vout). The table formatting has moved the Vout to the next line due to limited horizontal space.

0 Danilo A. over 3 years ago in reply to Kyle Van Renterghem

TI__Mastermind 24715 points

Hi Kyle,

Thank you for the clarification. For TPS79101, if the resistors used in the voltage divider has 1% tolerance, what would be the expected minimum and maximum voltage output of the regulator?

Regards,

Danilo

0 Stephen Ziel over 3 years ago in reply to Danilo A.

TI__Mastermind 29320 points

Hi Danilo,

There is a very good app note that helps discuss the tolerance of your resistors in an adjustable regulator.
This depends on your effective tolerance of each resistor, and also how the feedback resistor interacts with the adjust current.
Please see the following link.

http://www.ti.com/lit/an/snva112a/snva112a.pdf?ts=1588262164821

Thanks,

- Stephen

0 Danilo A. over 3 years ago in reply to Stephen Ziel

TI__Mastermind 24715 points

Hi Stephen,

Thank you for sharing this application note. It is very useful.

Regards,

Danilo

0 Stephen Ziel over 3 years ago in reply to Danilo A.

TI__Mastermind 29320 points

Hi Danilo,

Let me know if you need further assistance.

If you give me the resistor values and effective tolerance for each resistor, I can run a statistical analysis for you as well.

Thanks,

- Stephen

0 Danilo A. over 3 years ago in reply to Stephen Ziel

TI__Mastermind 24715 points

Hi Stephen,

From the explanation of Kyle about the the error introduced by the voltage divider, the customer now understands why the output voltage of the regulator is lower than the expected values.

Thank you for your support.

Regards,

Danilo

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TPS791: Tolerance of Vref