EVAL-ADM1276EBZ Analog Devices, EVAL-ADM1276EBZ Datasheet - Page 28

• Manufacturer Part Number: EVAL-ADM1276EBZ
• Description: Power Management IC Development Tools EVALUATION BOARD
• Manufacturer: Analog Devices
• Type: Hot Swap & Power Distributionr
• Series: ADM1276r

Specifications of EVAL-ADM1276EBZ

• Rohs: yes
• Tool Is For Evaluation Of: ADM1276
• Input Voltage: 20 V
• Factory Pack Quantity: 1

ADM1276
bits, as well as pointer bits that indicate whether any of the four
other status registers need to be read for more detailed status
information.
In the ADM1276, a particular distinction is made between
faults and warnings. A fault is always generated by the hot swap
controller and is defined by hardware component values. Three
events can generate a fault:
•
•
•
When a fault occurs, the hot swap controller always takes
some action, usually to turn off the GATE pin, which is
driving the FET. A fault can also generate an SMBAlert on
the GPO2/ ALERT2 pin.
All warnings in the ADM1276 are generated by the power
monitor, which samples the voltage and current and then
compares these measurements to the threshold values set by the
various limit commands. A warning has no effect on the hot
swap controller, but it may generate an SMBAlert on the
GPO2/ ALERT2 output pin.
When a status bit is set, it always means that the status condition—
fault or warning—is active or was active at some point in the past.
When a fault or warning bit is set, it is latched until it is explicitly
cleared using either the OPERATION or the CLEAR_FAULTS
command. Some other status bits are live, that is, they always
reflect a status condition and are never latched.
STATUS_BYTE and STATUS_WORD Commands
The STATUS_BYTE and STATUS_WORD commands can
be used to obtain a snapshot of the overall part status. These
commands indicate whether it is necessary to read more
detailed information using the other status commands.
The low byte of the word returned by the STATUS_WORD
command is the same byte returned by the STATUS_BYTE
command. The high byte of the word returned by the
STATUS_WORD command provides a number of bits that
can be used to determine which of the other status commands
needs to be issued to obtain all active status bits.
STATUS_INPUT Command
The STATUS_INPUT command returns a number of bits
relating to voltage faults and warnings on the input supply.
STATUS_VOUT Command
The STATUS_VOUT command returns a number of bits
relating to voltage faults and warnings on the output supply.
STATUS_IOUT Command
The STATUS_IOUT command returns a number of bits
relating to current faults and warnings on the output supply.
Overcurrent condition that causes the hot swap timer to
time out.
Overvoltage condition on the OV pin.
Undervoltage condition on the UV pin.
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STATUS_MFR_SPECIFIC Command
The STATUS_MFR_SPECIFIC command is a standard PMBus
command, but the contents of the byte returned are specific to
the ADM1276.
CLEAR_FAULTS Command
The CLEAR_FAULTS command is used to clear fault and
warnings bits when they are set. Fault and warnings bits are
latched when they are set. In this way, a host can read the bits
any time after the fault or warning condition occurs and
determine which problem actually occurred.
If the CLEAR_FAULTS command is issued and the fault or
warning condition is no longer active, the status bit is cleared.
If the condition is still active—for example, if an input voltage
is below the undervoltage threshold of the UV pin—the
CLEAR_FAULTS command attempts to clear the status bit, but
that status bit is immediately set again.
GPO AND ALERT PIN SETUP COMMANDS
A multipurpose pin is provided on the ADM1276:
GPO2/ ALERT2 . The GPO2/ ALERT2 pin can be configured
over the PMBus in one of three output modes, as follows:
•
•
•
In digital comparator mode, the current, voltage, and power
warning thresholds are compared to the values read or
calculated by the ADM1276. The comparison result sets the
output high or low according to whether the value is greater or less
than the warning threshold that has been set.
For an example of how to configure this pin to generate an
SMBAlert and how to respond and clear the condition, see the
Example Use of SMBUS Alert Response Address section.
ALERT2_CONFIG Command
Using combinations of bit masks, the ALERT2_CONFIG
command can be used to select the status bits that, when set,
generate an SMBAlert signal to a processor, or control the
digital comparator mode. They can also be used to set a GPO
mode on the GPO2/ ALERT2 pin, so that it is under software
control. If this mode is set, the SMBAlert masking bits are
ignored.
POWER MONITOR COMMANDS
The ADM1276 provides a high accuracy, 12-bit current and
voltage power monitor. The power monitor can be configured
in a number of different modes of operation and can run in
either continuous mode or single shot mode with a number
of different sample averaging options.
General-purpose digital output.
Output for generating an SMBAlert when one or more
fault/warning status bits become active in the PMBus
status registers.
Digital comparator.
Data Sheet