REF2025：The function test determines that the reference voltage is low

Tony zeng

Part Number: REF2025

Material description: precision voltage reference - fixed type - 2.5v-0.05% - 20ppm / ℃ - sot23-5-rohs
Discovery location: function test
Defect description: the function test determines that the reference voltage is low, and the standard value is 2.5v-0.05% (2.49875 ~ 2.50125v)
Defective rate: = 47 / 500 = 9.40%
DC: 2137

Disconnect the load, input voltage 4.9v, test and verify

Replace other chips for cross validation

Six circuit boards were verified and found to have this problem。Many tests have found that the problems exist. I hope I can get help and reply.

over 3 years ago

0 Tony zeng over 3 years ago

Prodigy 105 points

Test process
1. I test the fault unit, disconnect the load, input voltage 4.9v, and get the fifth pin: VREF voltage 2.495v, Vbias voltage 1.247v. In the actual production process, 49 of 500 pieces were used.
2、since its not new application. have you changed anything in your？
No change
3. We replaced the unit without problem with the suspected faulty chip for testing, but this problem still occurred. It was normal to replace other chips for testing, and cross verification was carried out.

0 Masoud Beheshti61 over 3 years ago in reply to Tony zeng

TI__Mastermind 18481 points

Hello Tony -

Thank you for contacting us.

There has not been any changes to this device.

Would you be able to share the test circuit with us?

Thank you.

0 Tony zeng over 3 years ago in reply to Masoud Beheshti61

Prodigy 105 points

Thank you very much for your reply
I very much hope to get your help. I try to provide the information I can provide. What do I need to do next?

Thank you.

0 Masoud Beheshti61 over 3 years ago in reply to Tony zeng

TI__Mastermind 18481 points

Hello Tony,

We can review your test circuit and procedure to see if your results are related to that or something else. Thanks.

0 Tony zeng over 3 years ago in reply to Masoud Beheshti61

Prodigy 105 points

Hello Masoud

Is it necessary for us to provide the design circuit diagram? I need some time for this.

0 Masoud Beheshti61 over 3 years ago in reply to Tony zeng

TI__Mastermind 18481 points

Hello Tony,

This is entirely up to you. Based on the information provided thus far, I do not have any other feedback on your original question.

Thank you.

0 Tony zeng over 3 years ago in reply to Masoud Beheshti61

Prodigy 105 points

Hello Masoud

This is the peripheral circuit design, please check it. If you have any other questions, please feel free to contact me. Thank you

0 Masoud Beheshti61 over 3 years ago in reply to Tony zeng

TI__Mastermind 18481 points

Hello Tony,

Thank you for sharing. The test circuit appears to be correct.

Please note the test conditions in the datasheet. The 0.05% spec is at 25C and with input voltage of 5V. You need to further account for variation based on the specified temperature coefficient and your test temperature. Hope that helps.

0 Tony zeng over 3 years ago in reply to Masoud Beheshti61

Prodigy 105 points

Can there be on-site FAE support, so that we can have a more comprehensive understanding of this problem，Thank you.

0 Tony zeng over 3 years ago in reply to Masoud Beheshti61

Prodigy 105 points

We conducted interactive verification, and it was normal to replace other batches. The problem of replacing suspected faulty units with normal circuit boards still existed.