UCD9090
SLVSA30A –APRIL 2011–REVISED AUGUST 2011
www.ti.com
A low impedance (short) on either address pin that produces a voltage below the minimum voltage causes the
PMBus address to default to address 126 (0x7E). A high impedance (open) on either address pin that produces
a voltage above the maximum voltage also causes the PMBus address to default to address 126 (0x7E).
Address 0 is not used because it is the PMBus general-call address. Addresses 11 and 127 can not be used by
this device or any other device that shares the PMBus with it, because those are reserved for manufacturing
programming and test. It is recommended that address 126 not be used for any devices on the PMBus, because
this is the address that the UCD9090 defaults to if the address lines are shorted to ground or left open. Table 10
summarizes which PMBus addresses can be used. Other SMBus/PMBus addresses have been assigned for
specific devices. For a system with other types of devices connected to the same PMBus, see the SMBus device
address assignments table in Appendix C of the latest version of the System Management Bus (SMBus)
specification. The SMBus specification can be downloaded at http://smbus.org/specs/smbus20.pdf.
34
Copyright © 2011, Texas Instruments Incorporated
TI [ TEXAS INSTRUMENTS ]
