THVD1400: THVD1400DR transmission distance issue

jeno.zhang

Part Number: THVD1400

hi，

The customer uses THVD1400DR as the RS485 transceiver, the sending end is powered by 3.3V, the receiving end uses 5V power supply and point-to-point communication. Does it affect the transmission distance？

In order to reduce power consumption, the customer does not want to add matching resistors, the transmission distance requirement is 200 meters. Does not adding a matching resistor affect the transmission distance?

Thanks！

over 1 year ago

0 Clemens Ladisch over 1 year ago

Guru 316690 points

Proper termination prevents reflections. Without termination, the maximum achievable speed is much lower.

If you want to reduce power consumption, consider using AC termination; see RS-485 Basics: When Termination Is Necessary, and How to Do It Properly.

0 Amy over 1 year ago

TI__Genius 15321 points

Hello,

The transmission distance is a function of the data rate and cable length. The data rate and cable length have an inverse relationship, meaning that the higher the data rate, the shorter the allowable cable length, and the lower the data rate, the long the cable length. The maximum bus length is limited by reflections and the jitter at a given data rate. Optimizing the jitter allows for greater bus distance. Without proper termination, the bus will likely see large reflections that degrade signal integrity.

Please refer to this TI video reference for further clarification: How far and fast can RS-485 communicate? | Video | TI.com

Regards, Amy

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THVD1400: THVD1400DR transmission distance issue