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LM5066 SMBus Connections

I am going to connect and LM5066 to an AM3359 I2C bus 2.  I am not sure if I am supposed to connect the SDAI and SDAO lines together.  There is a forum post on here relating to the LM5064 that says to use an ISO1540 to separate them, but the dev kit and the datasheet for the LM5066 show the lines as directly connected.  There is nothing else on I2C bus 2.

Is there a particular pin on the AM3359 (ZCZ) that I should use for the SMB Alert! signal, like a 'driver default' pin?

1 Reply

  • Hi Nick,

    On the LM5066, the SDAI and SDAO lines should be connected together if you don't require isolation.  The isolation is mentioned specifically on the LM5064 because the ground of that device is referred to the negative supply rail, and many applications require that the master communication rail is relative to the ground of the system.  In this case, you would need isolation to use the PMBus on the LM5064.

    Unfortunately I'm not familiar enough with the AM3359 to recommend a pin.  The alert signal is an open-collector output on the LM5066.