MAX3232: DOUT voltage issue

NAOKI AOYAMA

Guru 11215 points

Part Number: MAX3232
Other Parts Discussed in Thread: STRIKE

Hello,

Our customer use the MAX3232, have an issue of DOUT voltage.

The customer observe DOUT voltage as 1V. The DOUT1 voltage is 5V, it is no problem.

Only the DOUT2 voltage is 1V.

When RS232 cable disconnect, the voltage of the DOUT is 5V.

The customer use the MAX3232 at 3.3V and C1-C4 is 0.1uF. The customer change the capacitor

from 0.1uF to 0.47uF, it occur same issue.

Is this device damaged?

I attach the scope shot of V+/- voltage.

MAX3232_V+voltage.pdf

Best Regards,

Naoki Aoyama

over 6 years ago

0 Hao L over 6 years ago

TI__Mastermind 25705 points

Naoki-san,

The V+/V- look OK to me, although I'm not quite sure how AC couple test was set up, like what the coupling capacitor value is. It looks like Dout2 driver is broken while Dout1 is not. Has the device got any ESD strike, especially on Dout1 and Dout2 pins?

Regards,

0 NAOKI AOYAMA over 6 years ago in reply to Hao L

Guru 11215 points

Hello Hao,

Thank you for your reply.

I forget to attach the scope shot of DOUT issue.

MAX3232_DOUT.pdf

Is it damaged by ESD?

Regards,

Naoki Aoyama

0 Hao L over 6 years ago in reply to NAOKI AOYAMA

TI__Mastermind 25705 points

Naoki-san,

It's hard to say which part of circuitry went wrong from the waveform. If you want, you can send us the failure parts, we will try some tests or analysis.

Regards,

0 NAOKI AOYAMA over 6 years ago in reply to Hao L

Guru 11215 points

Hi Hao-san,

Thank you for your reply.
I will send TI the parts if the customer require analysis.

Thanks,
Naoki Aoyama

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MAX3232: DOUT voltage issue