[General] minor question regarding the SN75176A

[arbj2]

Hi,

I have this small query regarding the SN75176, RS 485 bus transceiver. See datasheet **broken link removed**

Say the IC is not powered via pin 8, now if the IC is connected to other SN75176 via pin 6 and pin 7 (RS 485 bus lines), will there be any voltage in pins 1,3 and 4 ??

Unfortunately I do not have the hardware with so I cannot confirm this, but has anyone observed this to happen ??

thanks
a

 

[FvM]

The bus pins have decoupling diodes that allow the bus to be driven safely beyond the supply rails, also with unpowered transceiver. I guess, there may be a small, current limited voltage fed to Vcc and signal pins, but without danger of damaging the connected circuit.

 

[arbj2]

thanks for the reply.

that was helpful