Simple SN65HVD12-replacement with SN65HVD72 possible?

Matthias Born

Other Parts Discussed in Thread: SN65HVD12, SN65HVD72

Hello,

currently I use a SN65HVD12 to make a RS485-communication happen.
This works quite well.

But I think that in some circumstances the "network" does some unhealthy stuff to my PCB.

--> The reason is probably the external bias resistor network which is connected via pull-up/down-resistors to a power-supply on my board

Now i want to get rid of the bias resistor network

Here i found some answers on my questions.
http://www.ti.com/lit/an/slyt514/slyt514.pdf

Questions:

Can I easily replace the SN65HVD12 with a SN65HVD72 (which doesn't require a external bias resistor network)?

Can I get trouble with customers? Because I don't know how the implemented the RS485-interface.

Am I missing a aspect which doesn't allow the suggested replacement?

Kind Regards

over 7 years ago

0 Max Robertson over 7 years ago

TI__Guru 62910 points

Hi Matthias,

As long as the HVD72's lower maximum data rate of 250 kbps is not a problem for the intended application, then is it OK to replace HVD12 with HVD72. Both devices are compliant to the the RS-485 standard, so they should be interoperable with one another. One detail to keep in mind is that the bus input leakage current is slightly higher for the HVD72, so if this is a very heavily-populated network you may need to restrict the maximum number of nodes. (To support the loading conditions defined in the RS-485 standard, you could use a maximum of 256 HVD12 devices or a maximum of 213 HVD72 devices on a shared bus.)

Please let me know if you have any other questions.

Best regards,
Max

0 Matthias Born over 7 years ago in reply to Max Robertson

Prodigy 20 points

Hi Max,

thanks for your detailed answer.
Bus-speed and node-count are ridiculous low ... so there is probably no problem =)

Best regards,
Matthias

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Simple SN65HVD12-replacement with SN65HVD72 possible?