This thread has been locked.
If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.
TPS7A49 Vfb versus Vref
Part Number: TPS7A49
We use TPS7A4901DRBR to convert 5V-->3.3V , 5V-->2.5V, 5V-->1.8V, and 5V.3-->5V.
Just to make sure: VREF is voltage measured at NR/SS pin, and it is 1.188V, with 1.176V~1.212V range. And VFB is 1.185V±2.5%. Is this understanding correct?
Why bother to give out these two value ? VREF seems to be useless in designing process.
I thought we all we need is to use VFB=1.185V±2.5% to calculate Vout's nominal and max, min value, and consider tolerance of R1 and R2 at the same time.
If I was wrong, pls point out. Thanks.
Correct the NR/SS pin is directly connected to the internal reference. As such, if you are attempting to measure the internal reference, you would use the NR/SS pin.
You are also correct that when selecting your resistors, you should use Vfb in your calculation. Vref is given for information purposes only.
As you mention, the accuracy stated in the datasheet includes all internal sources inaccuracy; however, it does not include the external resistor divider tolerance. In order to calculate the impact of the external resistors on your overall rail accuracy, please refer to the following Application Report:
We are glad that we were able to resolve this issue, and will now proceed to close this thread.
If you have further questions related to this thread, you may click "Ask a related question" below. The newly created question will be automatically linked to this question.
All content and materials on this site are provided "as is". TI and its respective suppliers and providers of content make no representations about the suitability of these materials for any purpose and disclaim all warranties and conditions with regard to these materials, including but not limited to all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement of any third party intellectual property right. No license, either express or implied, by estoppel or otherwise, is granted by TI. Use of the information on this site may require a license from a third party, or a license from TI.
TI is a global semiconductor design and manufacturing company. Innovate with 100,000+ analog ICs andembedded processors, along with software, tools and the industry’s largest sales/support staff.