Datasheet

MAX34451 PMBus 16-Channel V/I Monitor and
12-Channel Sequencer/Marginer
www.maximintegrated.com
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Password Protection
The device can be password protected by using the
LOCK bit in the MFR_MODE command. Once the
deviceislocked,onlycertainPMBuscommandscanbe
accessedwiththeserialport.SeeTable3foracomplete
listofPMBuscommands.Commandsthathavepassword
protectionreturnallones(FFh),withthepropernumber
ofdatabytes,whenread.Whenthedeviceislocked,only
the PAGE, OPERATION, CLEAR_FAULTS, and MFR_
SERIALcommandscanbewritten;allotherwrittencom-
mands are ignored. When MFR_SERIAL is written and
the upper 4 bytes match the internally flash-stored value,
thedeviceunlocksandremainsunlockeduntiltheLOCK
bit in MFR_MODE is activated once again. The LOCK
statusbitinSTATUS_MFR_SPECIFICisalwaysavailable
to indicate whether the device is locked or unlocked.
Power-Supply Sequencing
Sequencing control for each of the 12 power-supply
channels on the device is configured using the
MFR_SEQ_CONFIGandON_OFF_CONFIGcommands.
See the descriptions of these commands for detailson
theexactdeviceconfigurationrequired.Powersupplies
can be powered up and down in any order (even across
multiple devices). See the command descriptions and
Figure2forspecificsonsequencingcontrol.
Dual-Loop Sequencing
The device contains two independent sequencing groups,
SEQUENCE0 and SEQUENCE1. Both groups do not
need to be used, but every channel is assigned to one of
thetwogroupswith theSEQ_SELECTbit intheMFR_
SEQ_CONFIG command. The two sequencing groups
operate independently. SEQUENCE0 is always associ-
atedwithCONTROL0andSEQUENCE1isalwaysasso-
ciatedwithCONTROL1.Thetwosequencinggroupscan
also be independently controlled with the OPERATION
command. With the ON_OFF_CONFIG command, the
device is configured to respond to the CONTROLn
pinsorthe OPERATIONcommand (orboth).Whenthe
OPERATIONcommand is senttothedevice(whenthe
PAGE is set to 255), both sequence groups are con-
trolled,asshowninTable8.
Figure 2. Sequence Control Logic
MFR_TON_SEQ_MAX
SEQ MATCH
SELECT
SELECTON_OFF_CONFIG
MFR_SEQ_CONFIG
BITS 31:16 BIT 0 BITS 11:8 BITS 5:4
BIT 14BIT 26BIT 25BIT 24
SEQUENCE0
SEQUENCE1
OR
AND
AND
OR
J
K
ON
OFF
STOPSTART
PSEN0–PSEN11
POWER–S UPPLY
ENABLES
SEQ
(OPTIONAL FUNCTION
OF PSEN11)
POWER-ON
OPERATION COMMAND
CONTROL0
CONTROL1
PG0/GPI0–PG15/GPI15
FAULT0
FAULT1
(OPTIONAL FUNCTION
OF PWM7)
FAULT2
(OPTIONAL FUNCTION
OF PSEN10)
16
16
GLOBAL/
LOCAL
SELECT
OR
AND
AND
AND
GLOBAL
LOCAL
MFR_FAULT_RESPONSE
LOCAL0–LOCAL11
NOTE: SIGNALS LISTED IN ITALICS ARE INTERNAL SIGNALS THAT CONNECT TO OTHER DEVICE FUNCTIONS. SHADED BLOCKS ARE PMBus COMMANDS.