TL431B Vref measurement

PYTsai

Other Parts Discussed in Thread: TL431

Hi All,

My customer is using below circuit to measure TL431B Vref voltage (TA=25C), from datasheet the Vref should be 2.495V. However the Vref my customer measured is 2.477V. Any idea why the Vref falling outside datasheet spec? thansk!

over 7 years ago

0 Christopher Dean over 7 years ago

TI__Intellectual 1745 points

Hi PYTsai,

Can you contact me and we can try to figure out what is going on?

Chris

0 Michael J Schultis over 7 years ago in reply to Christopher Dean

TI__Mastermind 24485 points

Hello PYTsai,

The schematic seems fine, the key is to make sure that at least 1 mA is flowing into the cathode of the TL431.
According to the schematic it should be on the order of about 8 mA, so it should be fine.
Is this design on multiple boards? Do many of the boards work but some don't?

Do you have a layout that you can share to see if I can find anything?

Best,
Michael

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TL431B Vref measurement