LM2904: Output is abnormal

Sam Sun

Part Number: LM2904

Tool/software:

output voltage is bigger or smaller than Theoretical.

0 Ashley Kang 2 months ago

Hi Sam,

Could you clarify what the expected and measured input and output voltages were? Also, what is VCC value?

Regards,
Ashley

0 Sam Sun 2 months ago in reply to Ashley Kang

Hi Ashley,

Output range is 0~2.2V,VCC is 5v

0 Clemens Ladisch 2 months ago in reply to Sam Sun

Guru 268180 points

Please show the measured voltages at pins 1, 2, and 3.

0 Ashley Kang 1 month ago in reply to Clemens Ladisch

Hi Sam,

Are there any updates to this thread or further questions?

In the meantime, I will mark this thread as "TI Thinks Resolved" but please let us know if there is additional information or questions.

Thank you!
Regards,
Ashley

0 Sam Sun 1 month ago in reply to Ashley Kang

Hi Ashley,

Please refer below wave picture, there is one random channel failure in one chip.

0 Ashley Kang 1 month ago in reply to Sam Sun

Hi Sam,

Could you clarify what these waveforms correspond to on the op amp pins? Are these the output waveforms?

If the waveforms are the outputs what are the inputs?

Regards,
Ashley

0 Sam Sun 1 month ago in reply to Ashley Kang

INPUT1&2，PIN3 and PIN5 wave are same,PIN2 and PIN6 connected to GND.

abnormal ouput channel is randonm, failure pcs always has one channel out put as above,PIN1 OR PIN7

good output as above, the gap between good and ng is about 100mv.

the magnification is about 21.

0 Ashley Kang 1 month ago in reply to Sam Sun

Hi Sam,

Has the customer tested this outside of their system? Also, what is the intended input signal?

Regards,
Ashley

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