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CD4504B: Logic forum

Hui Cao22

Expert 1250 points

Part Number: CD4504B

Tool/software:

I am currently using the CD4504BM96 hexadecimal level converter to perform TTL to CMOS level conversion on PWM signals (5V to 15V).

The PWM pin of the controller TMS320F28377 is directly connected to the above-mentioned level converter.

when power up, the PWM wave is normal, but the PWM_A_G1 have a 15 V voltage ,the other PWM is 0V, and change a new chip, that is OK, The problem follows the bad chip.

Previously, mass production was fine, but recently there have been over ten pieces. What could be the reason for this. There are already more than ten chips in this situation. What could be the reason for this.

0 Jack Guan 6 months ago

TI__Mastermind 48991 points

Hi Hui,

We are still looking into this and will provide a response soon.

Regards,

Jack

0 Joshua Salinas 6 months ago

TI__Mastermind 32200 points

Hello Hui,

I have a couple of questions:

1) Has anything in your layout changed?

2) Can you confirm if any shorts from VCC or Vdd have occurred on the I/O lines?

3) Are all 15V output signals not working or only a couple?

Regards,

Josh

0 Hui Cao22 6 months ago in reply to Joshua Salinas

Expert 1250 points

1) Has anything in your layout changed? No.

2) Can you confirm if any shorts from VCC or Vdd have occurred on the I/O lines? No, change new chip, it's OK.

3) Are all 15V output signals not working or only a couple? yes, Only PWM A G1, one channel.

0 Joshua Salinas 6 months ago in reply to Hui Cao22

TI__Mastermind 32200 points

Hello Hui,

Let me clarify question 2. Can you check with a multimeter if there are any shorts from VCC/Vdd to I/O pins?

If we do notice shorts then EOS event most likely occurred.

Lastly, it could be related to a bad batch. I don't see any die refresh for this device so we are still shipping the same part as we did years ago.

Regards,

Josh