lm25066apsqx National Semiconductor Corporation, lm25066apsqx Datasheet - Page 30

• Manufacturer Part Number: lm25066apsqx
• Description: Lm25066a System Power Management And Protection Ic With Pmbus
• Manufacturer: National Semiconductor Corporation

www.national.com
OPERATION Register
The OPERATION command is a standard PMBus ™ com-
mand that controls the MOSFET switch. This command may
be used to switch the MOSFET ON and OFF under host con-
trol. It is also used to re-enable the MOSFET after a fault
triggered shutdown. The host must clear the fault condition
prior to re-enabling the MOSFET in this situation. The OP-
ERATION command is issued with the write byte protocol.
CLEAR FAULTS
The CLEAR FAULTS command is a standard PMBus ™ com-
mand that resets all stored warning and fault flags and the
SMBALERT signal. If a fault or warning condition still exists
when the CLEAR_FAULTS command is issued, the SM-
BALERT signal may not clear or will re-assert almost imme-
diately. Issuing a CLEAR_FAULTS command will not cause
the MOSFET to switch back on in the event of a fault turnoff;
that must be done by issuing an OPERATE command after
the fault condition is cleared. This command uses the PM-
Bus ™ send byte protocol.
CAPABILITY
The CAPABILITY command is a standard PMBus ™ com-
mand that returns information about the PMBus ™ functions
supported by the LM25066A. This command is read with the
PMBus ™ read byte protocol.
TABLE 2. Recognized OPERATION Command Values
Value
Value
B0h
80h
00h
TABLE 3. CAPABILITY Register
Supports Packet
400Kbits/sec,
Error Check,
SMBALERT
Switch OFF
Switch ON
Supports /
Meaning
Meaning
Default
Default
B0h
80h
n/a
30
VOUT_UV_WARN_LIMIT
The VOUT UNDERVOLTAGE WARN LIMIT is a standard
PMBus ™ command that allows configuring or reading the
threshold for the VOUT Undervoltage Warning detection.
Reading and writing to this register should use the coefficients
shown in the Telemetry and Warning Conversion Coefficients
Table. Accesses to this command should use the PMBus ™
read or write word protocol. If the measured value of VOUT
falls below the value in this register, VOUT UV Warn flags are
set and the SMBALERT signal is set.
OT_FAULT_LIMIT
The OVERTEMPERATURE FAULT LIMIT is a standard PM-
Bus ™ command that allows configuring or reading the thresh-
old for the Overtemperature Fault detection. Reading and
writing to this register should use the coefficients shown in the
Telemetry and Warning Conversion Coefficients Table. Ac-
cesses to this command should use the PMBus ™ read or
write word protocol. If the measured temperature exceeds this
value, an Overtemperature fault is triggered and the MOSFET
is switched off, OT Fault flags set and the SMBALERT signal
set. After the measured temperature falls below the value in
this register, the MOSFET may be switched back on with the
OPERATE command.
OT_WARN_LIMIT
The OVERTEMPERATURE WARN LIMIT is a standard PM-
Bus ™ command that allows configuring or reading the thresh-
old for the Overtemperature Warning detection. Reading and
writing to this register should use the coefficients shown in the
Telemetry and Warning Conversion Coefficients Table. Ac-
cesses to this command should use the PMBus ™ read or
write word protocol. If the measured temperature exceeds this
value, an Overtemperature warning is triggered and the OT
Warning flags set and the SMBALERT signal set.
Value
1h – 0FFFh
0000h
Value
0h – 0FFEh
0FFFh
Value
0h – 0FFEh
0FFFh
TABLE 4. VOUT Undervoltage Warn Limit Register
TABLE 6. Overtemperature Warn Limit Register
TABLE 5. Overtemperature Fault Limit Register
Meaning
VOUT
Undervoltage
Warning detection
threshold
VOUT
Undervoltage
Warning disabled
Meaning
Overtemperature
Fault Threshold
Value
Overtemperature
Fault detection
disabled
Meaning
Overtemperature
Warn Threshold
Value
Overtemperature
Warn detection
disabled
Default
0000h (disabled)
n/a
Default
0960h (150°C)
n/a
Default
07D0h (125°C)
n/a