ISOM8110: Cannot use ISOM8111 in RS485 under 115200bps baud rate

Peter Tseng

Mastermind 6210 points

Part Number: ISOM8110
Other Parts Discussed in Thread: ISOM8111, ISOM8710

Tool/software:

Hi Team,

The customer uses ISOM8111 on their RS485 isolation design.

The communication will fail while operating at high-speed baud rate (115200bps).

Please help to check and input your comments.

Thanks.

over 1 year ago

0 Clemens Ladisch over 1 year ago

Guru 317250 points

Please show the schematic.

+1 Andrew J over 1 year ago in reply to Clemens Ladisch

TI__Mastermind 29375 points

Hello Peter,

Thank you for reaching out. The ISOM811x family is an analog style opto-emulator. As a result, it does not have a high data rate when used for digital communications. From previous tests, I would recommend limiting the data through the opto-emulator to less than 100kBps. The ISOM8710 is designed to handle higher speed digital signals (up to 25MHz).

Otherwise, I would recommend one of TI's isolated RS-485 transceivers (like ISO1452) or digital isolators used with a non-isolated transceiver (ISO7741).

Best,
Andrew

Isolation

Isolation forum

ISOM8110: Cannot use ISOM8111 in RS485 under 115200bps baud rate