TPS53676 is designed to be compatible with the timing and physical layer electrical characteristics of the Power Management Bus (PMBus) Specification, part I, revision 1.3.1 available at http://pmbus.org. The 100-kHz, 400-kHz, and 1000-kHz classes are supported. Input logic levels are designed to be compaitible with 1.8-V and 3.3-V logic. PMBus revision 1.3 is derived from the System Managmenet Bus (SMBus) revision 3.0, available at http://smbus.org/. The communication mechanism is based on the inter-integrated circuit I²C protocol.

A master with clock stretching support is mandatory for communication with TPS53676 through the PMBus interface. TPS53676 does support the packet error check (PEC) protocol. If the system host supplies clock pulses for the PEC byte, PEC is used. If the CLK pulses are not present before a STOP, the PEC is not used. TPS53676 can be configured to require PEC for each transaction in systems which require high reliability of communication.

TPS53676 supports the SMB_ALERT# response protocol. The SMB_ALERT# response protocol is a mechanism by which a slave device can alert the master device that it is available for communication. The master device processes this event and simultaneously accesses all slave devices on the bus (that support the protocol) through the alert response address (ARA). Only the slave device that caused the alert acknowledges this request. The host device performs a modified receive byte operation to ascertain the slave devices address. At this point, the master device can use the PMBus status commands to query the slave device that caused the alert. By default, these devices implement the auto alert response, a manufacturer specific improvement to the SMB_ALERT# response protocol, intended to mitigate the issue of bus hogging. For more information on the SMBus alert response protocol, see the System Management Bus (SMBus) specification.