THVD9491-SEP: Question about two THVD9491-SEP communication.

Kazuhiko Hirano

Part Number: THVD9491-SEP

Tool/software:

Hello,

Two THVD9491-SEPs are communicating each other via RS-422. Now one power supply is off, the other power supply is on. In this case, is there a possibility that the THVD9491-SEP on the power OFF side will be damaged when the transmit signal is driven from the THVD9491-SEP on the power ON side?
In this case, my customer thinks that the THVD9491-SEP on the power OFF side is not damaged. Because, Table 7-4 of the datasheet shows when both VCC and VIO are less than UV, the receiver becomes Hi-Z. In addition, the bus voltage can withstand up to +/-70V as an absolute maximum rating. Is their understanding correct?

Best regards,

K.Hirano

9 months ago

0 Michael Ikwuyum 9 months ago

TI__Guru 50306 points

Hi Hirano-San,

We are currently on holiday.
Please help give our experts until next week for feedback, thanks.

Best Regards,

Michael.

0 Kazuhiko Hirano 9 months ago in reply to Michael Ikwuyum

TI__Genius 14978 points

Michael,

I understood.
I look forward to receiving feedbacks from experts next week.

Best regards,

K.Hirano

0 Michael Ikwuyum 9 months ago in reply to Kazuhiko Hirano

TI__Guru 50306 points

Hi Hirano-San,

Thanks for your patience.

Best Regards,

Michael.

+1 BOBBY 9 months ago

TI__Guru 72591 points

Hi K.Hirano,

Kazuhiko Hirano said:
In this case, my customer thinks that the THVD9491-SEP on the power OFF side is not damaged. Because, Table 7-4 of the datasheet shows when both VCC and VIO are less than UV, the receiver becomes Hi-Z. In addition, the bus voltage can withstand up to +/-70V as an absolute maximum rating. Is their understanding correct?

Yes, your customer is correct. You shouldn't see any damage since the device is 70V tolerant on its differential pins.

-Bobby

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THVD9491-SEP: Question about two THVD9491-SEP communication.