Datasheet

UCD9240
SLUS766C – JULY 2008 – REVISED NOVEMBER 2008 ................................................................................................................................................... www.ti.com
Table 1. PMBus Address Bins
V
PMBus
R
PMBus
PMBus VOLTAGE RANGE (V)
PMBus ADDRESS
PMBus RESISTANCE (k Ω )
MIN MAX
open 2.226 3.300 –
11 1.746 2.255 210
10 1.342 1.746 158
9 1.030 1.341 115
8 0.792 1.030 84.5
7 0.609 0.792 63.4
6 0.468 0.608 47.5
5 0.359 0.467 36.5
4 0.276 0.358 27.4
3 0.212 0.275 21.5
2 0.162 0.211 16.9
1 0.125 0.162 13.0
0 0.098 0.124 10.2
short 0 0.097 –
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. 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.
The PMBus address can be set to any value ranging from 1 to 126, except address 12. Address 0 is not used
because it is the SMBus General Call address; address 12 is reserved for the PMBus alert response. Also, it is
recommended that address 11 not be used by this device or any other device that shares the PMBus with it,
since it is used in manufacturing to program the device. Further, address 127 cannot be used by this device or
any other device that shares the PMBus with it, since the address is reserved by this device for device
manufacturing test.
Finally, it is recommended that address 126 not be used for any devices on the PMBus, since this is the address
that the UCD9240 defaults to if the address lines are shorted to ground or left open. If any other UCD9240 has a
short or open on its address lines, then its address would conflict with the (programmed) address 126.
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