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ADM2481 x ADUM5010

Question asked by JulianoCioffi on Jul 14, 2015
Latest reply on Jul 16, 2015 by JulianoCioffi

Hello support!

 

I have been studying this possibility a lot from Friday to today, and maybe someone can help me!

 

it is: ADM2481 being supplied by the ADUM5010. The reason is getting into a US$ 3.50 isolated rs-485 to beat our competitors.

 

I really could not find any information like is possible to find in the ADM2485 datasheet from current consumption vs data rate and termination resistors. It is only mentioned it needs isolated power supply of 5V 100mA in the line side.

 

I am convinced this transceiver can consume less than 30mA when using standard 120 ohms termination at 56 kbps that is almost 10x times less speed that the transceiver can handle.

 

My customer is planning to have 70 nodes on bus. Maybe the load considered would be 60 ohms since each node has its own 120 ohms resistor.

 

By looking at the ADM2587E at page 17 I could find some interesting information. (I know they are different structure transceivers but they can work with less current and voltages)

 

I know this solution has good chances to work, but cannot go against a datasheet recommendation and also I do not have enough information on provided graphs from 2481 to support my theory.

 

There is not even a differential output voltage x temperature, or current x differential output voltage in a way I can really know the values, because min and max values provided are too much wide in the driver parameters.

 

Thanks for your attention.

 

Att,

 

Juliano K. Cioffi - FAE 

Latinrep South America - Analog Devices

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