Rainbow Electronics MAX16064 - Manual (Page 24)

MAX16064
±0.3% Accurate, Quad, Power-Supply Controller with
Active-Voltage Output Control and PMBus Interface
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The hardwired address pins give 3 3 = 27 address
options. For example, to configure the MAX16064 to
have a slave address of 010 0101 (25h), set A3:A2:A1
= H:L:Z. The MAX16064 also responds to the broad-
cast address (00h).
If an EEPROM with valid SIGNATURE bytes is attached
to the MAX16064, the MAX16064 tries to restore its
slave address from the EEPROM. This overrides the
address set by the address pins. This gives a total of
128 possible slave addresses. Note that there are 14
reserved addresses that are restricted by the PMBus
specification and may not be used in PMBus systems.
If the address bit 7 from the EEPROM is set to 1, this is
an invalid address and the MAX16064 continues using
the address set by the address pins. When an
EEPROM is attached to A2/SDAE and A1/SCLE, these
pins assume either a logic-high or a logic-low level,
therefore, the resulting number of possible addresses
set by the A3:A2:A1 pins in this scenario is 2
3 = 8.
In addition, for the MAX16064 with an EEPROM
attached, the system controller can change the
MAX16064 slave address by sending the new address
with the MFR_SET_ADDRESS command. However, the
new address is not immediately effective. The new
address must be stored to the EEPROM first using the
STORE_DEFAULT_ALL command. Then, the
MAX16064 power must be cycled to start the address
assignment procedure and recalls the new address
from the EEPROM.
A3/CONTROL Operation
The A3/CONTROL input is utilized in combination with
the A2 and A1 inputs to set the PMBus address when
power is applied to the device. After the PMBus
address detection, the A3/CONTROL input functions as
the PMBus CONTROL input.
The ON_OFF_CONFIG command determines whether
the A3/CONTROL input affects the on/off behavior of the
power supply. When A3/CONTROL is enabled by the
ON_OFF_CONFIG command, a transition of A3/CON-
TROL from low to high turns the power supply on, as if
the MAX16064 has received an OPERATION ON
command. A transition of A3/CONTROL from high to low
initiates a soft-off to the power supply, as if the
MAX16064 has received an OPERATION OFF com-
mand (soft-off, with sequencing). The MAX16064 still
responds to the PMBus OPERATION command while
A3/CONTROL is enabled. To detect the A3/CONTROL
input, the A3/CONTROL signal pulse width has to satis-
fy the t
A3_LOW and t A3_HIGH requirements to be detect-
ed. See the ON_OFF_CONFIG (02h) section and Table
6 for more information.
Table 3. MAX16064 A3:A1 Slave Address Assignment (continued)
A3/CONTROL A2/SDAE A1/SCLE ADDRESS (BITS 7–1)
Z Z H 0Fh
L H L 12h
L H Z 13h
Z H L 16h
Z H Z 17h
L H H 1Bh
Z H H 1Fh
H L L 24h
H L Z 25h
H Z L 26h
H Z Z 27h
H L H 2Dh
H Z H 2Fh
H H L 36h
H H Z 37h
H H H 3Fh
* The shaded addresses are not available if external EEPROM is attached.