ISO7721: isolators application about RS232 & RS485

Kay Chen53

Part Number: ISO7721
Other Parts Discussed in Thread: MAX3221, ISO1410, THVD1450, ISO7741, ISOW7841, SN6501, THVD1451

Hi there:

Our customer would like to use line driver / receiver and isolator combination to full-fill the RS232 & RS485.

Dose those following combination could achieve that?

RS-232: MAX3221 & ISO7721

RS-485: THVD1450 & ISO7721 or ISO1410

If it's not suitable, do we have other suggestion could provide?

over 6 years ago

0 Lucas Schulte9 over 6 years ago

TI__Expert 6955 points

Kay,

Does the customer intend to isolate the R, RE, D, and DE pins? If so, the customer will need a 4 channel isolator such as the ISO7741. Otherwise the ISO1410 would be the single-chip solution with isolation integrated.

Respectfully,
Lucas

0 Kay Chen53 over 6 years ago in reply to Lucas Schulte9

Expert 2225 points

Hi Lucas:

Thanks again, customer need 4-channel for sure.

And would like to check does those combination work for RS-232 & RS-485 function?

0 user4786735 over 6 years ago in reply to Lucas Schulte9

Intellectual 460 points

Hi Lucas

I only have UART RXD/TXD. I don't have RE and DE.
If no RE and DE RS485 is work on THVD1450?

Shawn

0 Lucas Schulte9 over 6 years ago in reply to Kay Chen53

TI__Expert 6955 points

Kay,

For 4 channels the customer would need ISO7741. The ISO7721 is only 2 channels. The ISO7741 should work just fine. Does the customer have a way of achieving isolated DC to DC for Vcc1 anf Vcc2? If not, please consider using the SN6501/SN6505 transformer driver or the ISOW7841.

Respectfully,

Lucas

0 Lucas Schulte9 over 6 years ago in reply to user4786735

TI__Expert 6955 points

Shawn,

UART will require that the DE and RE be modulated as needed for either receiving or transmitting through the half-duplex RS-485 transceiver.

Respectfully,
Lucas

0 user4786735 over 6 years ago in reply to Lucas Schulte9

Intellectual 460 points

Hi Lucas

If I use THVD1451 and B connect to Z, A connect to Y. it is work on UART RX/TX to RS485?

0 Lucas Schulte9 over 6 years ago in reply to user4786735

TI__Expert 6955 points

Shawn,

This question will be better answered by the TRX product line. You can start a new thread specifically for the THVD1451 with your questions concerning that device. TRX has experts that can better answer questions concerning their devices, UART, and RS485.

Respectfully,

Lucas

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ISO7721: isolators application about RS232 & RS485