ISO3082: ISO3082 application problems

zhao zhaoyong

Intellectual 840 points

Part Number: ISO3082
Other Parts Discussed in Thread: ISO1410

Hello:

ISO3082 has encountered some problems in use. I need your help.

1. Prepare to connect DE and RE# pin directly to AST2500 GPIO pin for control, I wonder if it is ok?

2. When R,D pin is connected to AST2500 RXD and TXD pin, do I need to exchange pin?

3. Can both VCC1 and VCC2 use 3.3v power?

ISO3082_Schematic.pdf

Best Regards

Leon

文晔集团

广东省深圳市南山区高新中三道9号环球数码大厦12楼

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over 5 years ago

0 Koteshwar Rao over 5 years ago

TI__Guru 54685 points

Hi Leon,

Please find below my inputs.

1. Yes, DE and RE\ can be connected together to one GPIO pin of MCU for direction control without any issues. This is also described in Figure 27 under Section 9.2 of ISO3082 datasheet.

2. Yes, R should be connected to RXD pin while D should be connected to TXD pin of the MCU.

3. Unfortunately, ISO3082 VCC2 can only be operated with 5V±10% supply and it doesn't support 3.3V. Instead I would recommend using ISO1410 which is our latest isolated RS-485 transceiver that supports both 3.3V & 5V operation on the bus side (VCC2) while VCC1 can be operated for voltages 1.8V, 2.5V, 3.3V or 5V irrespective of VCC2.

ISO1410, being our latest isolated RS-485 transceiver, has many advantages over ISO3082. Please refer to the below E2E post to know more about the advantages of ISO1410 over ISO3082. Thanks.

e2e.ti.com/.../787278

Regards,
Koteshwar Rao

Isolation

Isolation forum

ISO3082: ISO3082 application problems