ADM2486 Ground connection

Question

Hello, 
 
 One customer is reviewing the ADM2486 for UART to RS485 converting. 
 1. Datasheet noticed the Vdd2 can only be 5V, I just want to know if 3.3v works or not. 
 
 2. Is there any problem for operation to connect GND1 and GND2 without isolation?

Thanks, 
 Gabe.

NQuinn · Accepted Answer

Hi Gabe, 
 Thank you for your query. 
 The ADM2486 will not operate reliably with a 3.3V VDD2 supply, the device accepts a supply voltage between 4.75V and 5.25V. 
 If the customer requires an isolated transceiver RS485 transceiver with a 3.3V supply on VDD2, the ADM2491E and ADM2482E are two good alternatives: 
 https://www.analog.com/media/en/technical-documentation/data-sheets/adm2491e.pdf 
 https://www.analog.com/media/en/technical-documentation/data-sheets/adm2482e_2487e.pdf 
 Both of these devices are full duplex transceivers, but can be configured as half duplex by connecting Pin Y to Pin A, and by connecting Pin Z to Pin B. 
 These isolated transceivers will continue to function if GND1 and GND2 are connected together. However by doing so the GND1 and GND2 will no longer be electrically isolated. Does the customer require that the UART and RS485 are electrically isolated? If so, the GND1 and GND2 must not be connected together. If isolation is not required I can recommended the recently released ADM3065E transceiver. 
 https://www.analog.com/media/en/technical-documentation/data-sheets/adm3061e-3062e-3065e-3066e.pdf 
 Regards, 
 Neil

Electronic Design Services - PartnerZone

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ADM2486 Ground connection

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