Maxim Integrated MAX15301 PMBus Command Set - Manual (Page 25)

MAX15301 PMBus Command Set User’s Guide
Rev 1 Page 25 of 53
OT_WARN_LIMIT
Reference: Standard Command Lockable: Yes
Command Code: 0x51 Format: Linear
Data Bytes: 2 Units: °C
Transfer: Read/Write Word Factory Value: 0xEAF8 (95°C)
Description/Notes: See Section 15.19 of the PMBus Specification Part II.
The MAX15301 has an internal temperature signal and can also measure temperature at an external
location, using a diode junction.
The OT_WARN_LIMIT applies to the external temperature signal, if a valid sensor is detected during
initialization. If no external sensor is detected, the OT_WARN_LIMIT applies to the internal
temperature signal instead.
Overtemperature fault hysteresis is achieved in the MAX15301 by using the OT_WARN_LIMIT as the
“fault cleared” threshold for
OT_FAULT_LIMIT . For this reason, it is important to always set
OT_WARN_LIMIT below OT_FAULT_LIMIT.
VIN_OV_FAULT_LIMIT
Reference: Standard Command Lockable: Yes
Command Code: 0x55 Format: Linear
Data Bytes: 2 Units: V
Transfer: Read/Write Word Factory Value: 0xD380 (14V)
Description/Notes: See Section 15.23 of the PMBus Specification Part II.
The MAX15301 hardware has 8-bit resolution for the input overvoltage fault limit, to a maximum
value of ≈14.75V.
The desired value of VIN_OV_FAULT_LIMIT is retained in memory, regardless limitations imposed by
the 8-bit fault limit resolution, but the read-back value is based on actual hardware register settings.
VIN_OV_FAULT_RESPONSE
Reference: Standard Command Lockable: Yes
Command Code: 0x56 Format: Bit field
Data Bytes: 1 Units: N/A
Transfer: Read/Write Byte Factory Value: 0xC0 (Shut down, restart when fault
abates)
Description/Notes: See Sections 10.5.1 and 15.24 of the PMBus Specification Part II.
Note that the MAX15301 does not support finite, non-zero restart-attempt counts. (Continuous
restart attempts are supported.)
The VIN_OV_FAULT_RESPONSE command data comprises three bit-fields:
Bits [7:6] determine the basic fault-response mode. The MAX15301 supports the following modes:
00 Ignore the fault condition.
01 Continue operating and wait for the fault to abate for time specified in bits [2:0]. If the
fault does not abate, shutdown and attempt to restart according to bits [5:3].