EVALUATION KIT AVAILABLE MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer General Description The MAX34460 is a system monitor that is capable of managing up to 12 power supplies. The power-supply manager monitors the power-supply output voltages and constantly checks for user-programmable overvoltage and undervoltage thresholds. If a fault is detected, the device automatically shuts down the system in an orderly fashion.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer TABLE OF CONTENTS General Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer TABLE OF CONTENTS (continued) Sending a DIRECT Format Value . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Fault Management and Reporting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Password Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer TABLE OF CONTENTS (continued) POWER_GOOD_OFF (5Fh) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 TON_DELAY (60h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 TOFF_DELAY (64h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer TABLE OF CONTENTS (continued) Margining Faults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 DAC Margining Component Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 Temperature-Sensor Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer LIST OF FIGURES Figure 1. PMBus-Defined Time-Based Sequencing Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Figure 2. Timeslot-Defined Event-Based Sequencing Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 Figure 3. Multiple Device Hardware Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer LIST OF TABLES (continued) Table 24. STATUS_MFR_SPECIFIC (for PAGE 255) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 Table 25. MFR_MODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 Table 26. PSENn Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer ABSOLUTE MAXIMUM RATINGS VDD and VDDA to VSS...........................................-0.3V to +4.0V SDA, SCL, MSDA, and MSCL to VSS....................-0.3V to +4.0V RSG0 and RSG1 to VSS........................................-0.3V to +0.3V RSn to VSS................................................ -0.3V to (VDD + 0.3V)* RSn to VSS with 100ω of series resistance...........-0.3V to +2.0V All Other Pins Relative to VSS.................. -0.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer ELECTRICAL CHARACTERISTICS (continued) (VDD and VDDA = 3.0V to 3.6V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at VDD/VDDA = 3.3V, TA = +25°C.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Output Logic-Low SCL, SDA, MSCL, MSDA VOL2 IOL = 4mA (Note 1) 0.4 V SCL, SDA, MSCL, MSDA Leakage ILI2C VDD = 0V or unconnected Q5 FA CONTROL Threshold 2.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer I2C/SMBus INTERFACE ELECTRICAL SPECIFICATIONS (VDD and VDDA = 3.0V to 3.6V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at VDD/VDDA = 3.3V, TA = +25NC.) PARAMETER SYMBOL SCL Clock Frequency CONDITIONS MIN 10 fSCL MSCL Clock Frequency TYP fMSCL MAX UNITS 400 kHz 100 kHz Bus Free Time Between STOP and START Conditions tBUF 1.3 Fs Hold Time (Repeated) START Condition tHD:STA 0.6 Fs Low Period of SCL tLOW 1.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer Typical Operating Characteristics (VDD = 3.3V and TA = +25°C, unless otherwise noted.) SUPPLY CURRENT vs. SUPPLY VOLTAGE SUPPLY CURRENT vs. TEMPERATURE 12.5 TA = +85°C 12.5 IDD (mA) IDD (mA) TA = +25°C 12.0 12.0 11.5 MAX34460 toc02 13.0 MAX34460 toc01 13.0 11.5 11.0 11.0 10.5 10.5 TA = -40°C 10.0 10.0 -20 -40 0 20 40 60 80 3.0 100 3.1 3.2 3.3 3.4 3.5 3.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer Typical Operating Characteristics (continued) (VDD = 3.3V and TA = +25°C, unless otherwise noted.) VOUT STEPS DURING MARGINING RST PIN DURING POWER-UP MAX34460 toc08 MAX34460 toc07 VOUT 50mV/div 1V/div VDD 1V/div RST 200µs/div 20ms/div IDD vs. TIME DURING A NONVOLATILE LOG WRITE IDD vs.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer ALARM1 ALERT A1/ PG PG2 CONTROL2 RSG0 RSG1 PSEN0 PSEN1 PSEN3 PSEN2 TOP VIEW PSEN4 Pin Configuration 36 35 34 33 32 31 30 29 28 27 26 25 PSEN5 37 24 ALARM0 PSEN6 38 23 PSEN11 PSEN7 39 22 PSEN10 WDO 40 21 PSEN9 WDI 41 20 PSEN8 RS11 42 19 MSDA MAX34460 RS10 43 18 MSCL RS9 44 17 FAULT2 RS8 45 16 REG18 RS7 46 RS6 47 15 VDD EP/ VSS + 14 SCL RS5 48 RS1 RS0 8 9 10 11 12 ALARMCLR RS2 7 RST RS3 6 CONTROL 5 N.C.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer Pin Description (continued) PIN* NAME TYPE** FUNCTION 10 CONTROL AI 11 RST DIO 12 ALARMCLR DI 13 SDA DIO I2C/SMBus-Compatible Input/Open-Drain Output 14 SCL DIO I2C/SMBus-Compatible Clock Input/Open-Drain Output 15 VDD Power Digital Supply Voltage. Bypass VDD to VSS with 0.1FF. Connect to VDDA. 16 REG18 Power Regulator for Digital Circuitry. Bypass to VSS with 1FF and 10nF (500mI maximum ESR).
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer Pin Description (continued) PIN* NAME TYPE** FUNCTION 38 PSEN6 DO Power-Supply Enable Output 6. See the Expanded Pin Description section for more details. 39 PSEN7 DO Power-Supply Enable Output 7. See the Expanded Pin Description section for more details. 40 WDO DIO Open-Drain, Active-Low Watchdog Input/Output. Can be configured with MFR_WATCHDOG_CONFIG as a manual reset input. 41 WDI DI Watchdog Input. Rising edge triggered.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer Block Diagram MSDA MSCL SDA SCL CONTROL2 SMBus MASTER SECONDARY SEQUENCER CONTROL FAULT2 PG2 SMBus SLAVE PULLUP LATCHED ALARM INDICATION ALERT FAULT ALARM0 ALARM1 PULLUP A0/MONOFF A1/PG PULLUP RST VDD REG18 ALARMCLR WDI PMBus CONTROL AND MONITORING ENGINE WATCHDOG WDO POWER-SUPPLY OUTPUT ENABLES PSEN0– PSEN11 12 POWER CONTROL CONTROL 1.8V VREG AUTO SEQUENCER EP/VSS VDDA 4 DIGITAL COMPARATORS ADC RESULTS SRAM VREF 2.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer output and then measures the resultant output voltage. The power-supply manager can also sequence the supplies in any order at both power-up and power-down. temperature sensors. Communications with the DS75LV temperature sensors is conducted through a dedicated I2C/SMBus interface.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer Table 1. PMBus Command Codes (continued) CODE COMMAND NAME TYPE PAGE 0–11 PAGE 13–17 PAGE 255 (NOTE 1) 99h MFR_ID 9Ah 9Bh NO.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer Address Select On device power-up, the device samples the A0 and A1 pins to determine the PMBus/SMBus serial-port address. The combination of the components shown below determines the serial-port address (see also Table 2). MAX34460 R1 SMBus/PMBus Operation The device implements the PMBus command structure using the SMBus format.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer SMBus/PMBus Communication Examples READ WORD FORMAT 1 7 S SLAVE ADDRESS 1 W 1 8 A COMMAND CODE 1 1 7 A Sr SLAVE ADDRESS 1 8 A COMMAND CODE A 1 1 8 1 8 1 1 R A DATA BYTE LOW A DATA BYTE HIGH NA P 1 1 7 1 1 8 1 1 SLAVE ADDRESS Sr R A DATA BYTE NA P READ BYTE FORMAT 1 7 S SLAVE ADDRESS 1 W WRITE WORD FORMAT 1 7 1 1 8 1 8 1 8 1 1 S SLAVE ADDRESS W A COMMAND CODE A DATA BYTE LOW A DATA
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer Group Command The device supports the group command. With the group command, a host can write different data to multiple devices on the same serial bus with one long continuous data stream. All the devices addressed during this transaction wait for the host to issue a STOP before beginning to respond to the command.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer Alert Response Address (ARA) Byte Format 1 7 1 1 8 1 1 S ARA 0001100 R A DEVICE SLAVE ADDRESS WITH LSB = 0 NA P Host Sends or Reads Too Few Bits If, for any reason, the host does not complete writing a full byte or reading a full byte from the device before a START or STOP is received, the device does the following: Host Sends Improperly Set Read Bit in the Slave Address Byte 1) Ignores the command.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer Host Reads from a Write-Only Command When a read request is issued to a write-only command (CLEAR_FAULTS, STORE_DEFAULT_ALL, RESTORE_ DEFAULT_ALL, OPERATION with PAGE = 255), the device does the following: 1) ACKs the address byte. 2) Ignores the command. 3) Sends all ones (FFh), as long as the host keeps acknowledging. 4) Sets the CML bit in STATUS_WORD. 5) Sets the DATA_FAULT bit in STATUS_CML.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer Table 3.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer Fault Management and Reporting For reporting faults/warnings to the host on a real-time basis, the device asserts the open-drain ALERT pin (if enabled in MFR_MODE) and sets the appropriate bit in the various status registers. On recognition of the ALERT assertion, the host or system manager is expected to poll the I2C bus to determine the device asserting ALERT. The host sends the SMBus ARA (0001 100).
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer PMBus-Defined Time-Based Sequencing Figure 1 details a simple sequencing scheme using four power supplies. When either the CONTROL pin goes active or the OPERATION command is received (as defined by the ON_OFF_CONFIG command), each enabled PSENn output goes active (can be active high or low, as defined in MFR_PSEN_CONFIG) after the associated delay time programmed in TON_DELAY. The power supplies can be sequenced on in any order.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer Timeslot-Defined Event-Based Sequencing As an example of timeslot sequencing, Figure 2 details a simple sequencing scheme using four power supplies.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer timeslot 2 begins. The power supplies can be sequenced on in any order. Since multiple power supplies can be assigned to a single timeslot, not all timeslots may be needed. However, timeslot assignment must be sequential. GLOBAL channels must start in timeslot 0, whereas local channels can be assigned to any timeslot. After all enabled supplies are turned on and above their respective power-good-on levels, the PG output transitions high.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer Table 6. Device Configuration Quick Reference ACTION CONFIGURATION Enable a channel Configure TON_MAX_FAULT_LIMIT = 0000h to 7FFFh. Disable a channel Configure TON_MAX_FAULT_LIMIT = 8000h to FFFFh.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer MONOFF Disable Monitoring Control Input The MONOFF control (which is shared with the A0 I2C slave address-select function) is an active-low input with an internal weak pullup. To allow the device to properly set the I2C address, this pin should be high impedance upon power-up or device reset (it is recommended that a small-signal MOSFET be used to pull this pin low). See the Typical Operating Circuit for an example.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer STARTUP FOR DEPENDENT MODE MFR_PG_DELAY POWER-GOOD WD_STARTUP PG WD_TIMEOUT WD_STARTUP WD_TIMEOUT WD_TIMEOUT WDI HIGH IMPEDANCE MFR_PG_DELAY HIGH IMPEDANCE WDO STARTUP FOR INDEPENDENT MODE 125ms WD_STARTUP VDD WD_TIMEOUT WD_TIMEOUT WD_TIMEOUT WD_STARTUP WDI HIGH IMPEDANCE MFR_PG_DELAY WDO HIGH IMPEDANCE WATCHDOG HARDWARE-CONTROL CONFIGURATIONS 10kI WDI 10kI PG WDO SYSTEM RESET SIGNAL PUSHBUTTON RESET OPTION ASSERTS SYSTEM RESET
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer PMBus Commands A summary of the PMBus commands supported by the device are described in the following sections. PAGE (00h) The device can monitor up to 12 voltages, sequence up to 12 power supplies, and margin up to 12 power supplies using three external current DACs (DS4424). The device can monitor up to five temperature sensors, one internal local temperature sensor, plus four external remote temperature sensors (DS75LV).
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer Set the PAGE command to 255 when the following PMBus commands should apply to all pages at the same time. There are only a few commands (OPERATION, CLEAR_FAULTS) where this function has a real application. OPERATION (01h) The OPERATION command is used to turn the power supply on and off in conjunction with the CONTROL input pin.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer Table 11. Special OPERATION Command Bytes for Primary Sequence COMMAND BYTE POWER SUPPLY ON/OFF MARGIN STATE 01h Immediate off (no sequencing) — 41h Soft-off (with sequencing) — 81h On Margin off Table 12.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer CLEAR_FAULTS (03h) The CLEAR_FAULTS command is used to clear any latched fault or warning bits in the status registers that have been set and also unconditionally deasserts the ALERT output. This command clears all bits simultaneously. The CLEAR_FAULTS command does not cause a power supply that has latched off for a fault condition to restart.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer RESTORE_DEFAULT_ALL (12h) The RESTORE_DEFAULT_ALL command transfers the default configuration information from the internal flash memory array to the user memory registers in the device. The RESTORE_DEFAULT_ALL command should only be executed when the device is not operating the power supplies. Upon a device power-on reset or any device reset, this command is automatically executed by the device without PMBus action required.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer VOUT_SCALE_MONITOR (2Ah) In applications where the measured power-supply voltage is not equal to the voltage at the ADC input, VOUT_SCALE_MONITOR is used. For example, if the ADC input expects a 1.8V input for a 12V output, VOUT_ SCALE_MONITOR = 1.8V/12V = 0.15. In applications where the power-supply output voltage is greater than the device’s 2.048V input range, the output voltage of the power supply is sensed through a resistive voltagedivider.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer VOUT_OV_FAULT_LIMIT (40h) The VOUT_OV_FAULT_LIMIT command sets the value of the output voltage that causes an output overvoltage fault. The monitored voltage must drop by at least 2% below the limit before the fault is allowed to clear. This fault is masked until the output voltage is below this limit for the first time. The 2 data bytes are in DIRECT format.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer OT_WARN_LIMIT (51h) The OT_WARN_LIMIT command sets the temperature, in degrees Celsius, of the selected temperature sensor at which an overtemperature warning is detected. The monitored temperature must drop by at least 4NC below the limit before the warning is allowed to clear. The 2 data bytes are in DIRECT format. In response to the OT_WARN_LIMIT being exceeded, the device does the following: 1) Sets the TEMPERATURE bit in STATUS_WORD.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer Table 18. TON_MAX_FAULT_LIMIT Device Response DEVICE RESPONSE (FOR EACH ASSOCIATED PAGE) (NOTE 1) SEQUENCING CONFIGURATION (NOTE 2) TON_MAX_ FAULT_LIMIT VALUE Standard SEQUENCING RESPONSE VOLTAGE FAULT MONITORING (NOTE 3) USE PSENn AS GPO (NOTE 4) 0001h to 7FFFh Device asserts PSENn and monitors RSn to cross the undervoltage-fault limit in the time set by TON_MAX_FAULT_LIMIT.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer STANDARD SEQUENCING TON_MAX_FAULT_LIMIT = 0001h TO 7FFFh MAX34460 SEQUENCER GPO PAGE n PSENn POWER SUPPLY ENABLE OV/UV MONITOR READ_VOUT / PG BLIND SEQUENCING TON_MAX_FAULT_LIMIT = 0000h RSn MAX34460 SEQUENCER GPO PAGE n PSENn READ_VOUT /PG RSn MAX34460 SEQUENCER POWER SUPPLY ENABLE VOUT OV/UV MONITOR MONITORING ONLY TON_MAX_FAULT_LIMIT = 0000h VOUT GPO VOLTAGE SOURCE PAGE n PSENn DIGITAL OUTPUT OV/UV MONITOR READ_VOUT/PG CHANNE
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer STATUS_VOUT (PAGES 0–11) EVENT LATCH EVENT LATCH VOUT_OV_WARN EVENT LATCH VOUT_UV_FAULT EVENT LATCH VOUT_UV_WARN EVENT LATCH TON_MAX_FAULT VOUT_OV_FAULT OR STATUS_CML (ALL PAGES) EVENT FAULT_LOG_FULL EVENT LATCH DATA_FAULT EVENT LATCH COMM_FAULT OR STATUS_TEMPERATURE (PAGES 13–17) EVENT LATCH OT_WARN EVENT LATCH OT_FAULT OR STATUS_MFR_SPECIFIC (PAGES 0–11) EVENT OFF EVENT POWER_GOOD# EVENT LATCH STATUS_WORD (ALL PA
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer STATUS_WORD (79h) The STATUS_WORD command returns 2 bytes of information with a summary of the reason for a fault. The STATUS_WORD message content is described in Table 19. See Figure 6 for status register organization. STATUS_VOUT (7Ah) The STATUS_VOUT command returns 1 byte of information with contents, as described in Table 20. All the bits in STATUS_VOUT are latched.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer STATUS_TEMPERATURE (7Dh) The STATUS_TEMPERATURE command returns 1 byte of information with contents, as described in Table 21. All the bits in STATUS_VOUT are latched. When cleared, the bits are set again if the condition persists. STATUS_CML (7Eh) The STATUS_CML command returns 1 byte of information with contents, as described in Table 22. The COMM_FAULT and DATA_FAULT bits are latched.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer STATUS_MFR_SPECIFIC (80h) The STATUS_MFR_SPECIFIC message content varies based on the selected page, and is described in Table 23 and Table 24. READ_VOUT (8Bh) The READ_VOUT command returns the actual measured (not commanded) output voltage. READ_VOUT is measured and updated every 5ms. The 2 data bytes are in DIRECT format. Table 23.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer READ_TEMPERATURE_1 (8Dh) The READ_TEMPERATURE_1 command returns the temperature returned from the temperature sensor. READ_ TEMPERATURE_1 returns 7FFFh if the sensor is faulty and 0000h if the sensor is disabled. READ_TEMPERATURE_1 is measured and updated once per second. The 2 data bytes are in DIRECT format. PMBUS_REVISION (98h) The PMBUS_REVISION command returns the revision of the PMBus specification to which the device is compliant.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer Table 25. MFR_MODE BIT NAME 15:14 MULTI_SEQ[1:0] 13 ALERT 12 SEQ 11 SOFT_RESET 10 LOCK 9:8 0 7:6 ADC_TIME[1:0] 5 DUAL_SEQ 4 FAULT_IGNORE MEANING These bits set the sequencing configuration for the primary sequencing group. The secondary sequencing group should not use cascaded sequencing if the group involves multiple devices. 00 = Single device or multiple devices with Common Control or Common OPERATION Command.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer MFR_PSEN_CONFIG (D2h) The MFR_PSEN_CONFIG command is used to configure the individual PSENn outputs. This command should not be changed while the power supplies are operating. The MFR_PSEN_CONFIG command is described in Table 26 and Table 27. Table 26.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer MFR_SEQ_TIMESLOT (D3h) The MFR_SEQ_TIMESLOT command is used in the timeslot-defined sequencing mode (SEQ bit in MFR_MODE is set) to determine which timeslot the PSENn output is associated with and the command is also used in the dual-sequencing mode (DUAL_SEQ bit in MFR_MODE is set) to assign channels to a group. In the timeslotdefined sequencing mode, multiple PSENn outputs can be assigned to the same timeslot.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer MFR_NV_LOG_CONFIG (D8h) The MFR_NV_LOG_CONFIG command is used to configure the operation of the nonvolatile fault logging in the device. The MFR_NV_LOG_CONFIG command is described in Table 29. Table 29. MFR_NV_LOG_CONFIG BIT NAME MEANING FORCE_NV_FAULT_LOG Setting this bit to a 1 forces the device to log data into the nonvolatile fault log. Once set, the device clears this bit when the action is completed.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer MFR_FAULT_RESPONSE (D9h) The MFR_FAULT_RESPONSE command specifies the response to each fault or warning condition supported by the device. In response to a fault/warning, the device always reports the fault/warning in the appropriate status register and asserts the ALERT output (if enabled in MFR_MODE). A CML fault cannot cause any device action other than setting the status bit and asserting the ALERT output.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer MONITORING 12 CHANNELS FAULT OVERVOLTAGE STATUS REGISTERS WARNING NV_FAULT_LOG FAULT UNDERVOLTAGE WARNING MFR_FAULT_RESPONSE SHUTDOWN SEQUENCING SEQUENCING ERROR FAULT TEMPERATURE SENSORS INTERNAL DS75LV DS75LV FAULT OR WARNING DS75LV DS75LV ON_OFF_CONFIG BIT 0 SHUTDOWN IMMEDIATELY OR SEQUENCE OFF GLOBAL BIT PSEN0 GLOBAL BIT PSEN1 GLOBAL BIT PSEN2 GLOBAL BIT PSEN3 GLOBAL BIT PSEN4 GLOBAL BIT PSEN5 GLOBAL BIT PSEN6 GLOBAL BIT
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer Logging Faults into MFR_NV_FAULT_LOG If bit 15 of MFR_FAULT_RESPONSE is set, faults are logged into the on-board nonvolatile fault log for this channel unless the response for the associated fault is configured to take no action (RESPONSE[1:0] = 00). To keep from needlessly filling the fault log with excessive data, the following rules are applied when subsequent faults occur.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer Table 32. MFR_FAULT_RESPONSE Codes for GLOBAL Channels RESPONSE[1:0] 11 10 (retry) 01 (latch off) 00 FAULT RESPONSE • Set the corresponding fault bit in the appropriate status register. • Log fault into MFR_NV_FAULT_LOG if NV_LOG = 1. • Continue operation. • Shut down the power supply by deasserting the PSENn output.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer Power-Supply Retry with Undervoltage Faults If the power supply is configured to retry when an undervoltage fault occurs, the power supply is turned off for the fault retry time and then the power supply is turned back on by asserting the PSENn output. If the undervoltage fault still exists, the TON_MAX_FAULT_LIMIT is exceeded and the device takes fault action as configured.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer There is a FAULT_LOG_COUNT (16-bit counter) at the beginning of each fault log that indicates which fault log is the latest. This counter rolls over should more than 65,535 faults be logged. This counter is not cleared when the CLEAR_NV_FAULT_LOG bit in MFR_NV_LOG_ CONFIG is toggled. The 255 bytes returned by the MFR_ NV_FAULT_LOG command are described in Table 34.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer Table 34.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer MFR_MARGIN_CONFIG (DFh) The MFR_MARGIN_CONFIG command configures the external DS4424 current DAC (if present) to margin the associated power supplies. The MFR_MARGIN_CONFIG command is described in Table 35. For the power supplies connected to PSENn (PAGES 0–11), power-supply margining is implemented using the external DS4424 DAC outputs, according to Table 36. The device’s closed loop controls the DAC output current setting to margin the power supply.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer Margining Faults The device detects two possible margining faults. First, if the initial DAC step causes VOUT to exceed the target value (either high or low depending on whether the device has been instructed to margin high or low, respectively), this creates a fault. Second, if the target value cannot be reached when the DAC reaches full scale, this also creates a fault.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer Table 38. MFR_TEMP_SENSOR_CONFIG BIT NAME 15 ENABLE 14:0 0 MEANING 0 = Temperature sensor disabled. 1 = Temperature sensor enabled. These bits always return a 0. Table 39. MFR_GPO_CONFIG MFR_TEMP_SENSOR_CONFIG (F0h) The MFR_TEMP_SENSOR_CONFIG command is used to configure the temperature sensors. The MFR_TEMP_ SENSOR_CONFIG command is described in Table 38.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer MFR_WATCHDOG_CONFIG (FDh) The MFR_WATCHDOG_CONFIG command is used to configure the external watchdog function. The MFR_WATCHDOG_CONFIG command is described in Table 40. Applications Information VDD, VDDA, and REG18 Decoupling To achieve the best results when using the device, decouple VDD and VDDA power inputs each with a 0.1FF capacitor. If possible, use a high-quality, ceramic, surface-mount capacitor.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer Configuration Port Some applications require the ability to configure the device when it has been mounted on a PCB. In such applications, a 3- or 4-wire header can be added to allow access to the slave I2C pins. Resistor-Dividers and Source Impedance for RSn Inputs The maximum full-scale voltage on the ADC inputs is 2.048V (nom). A resistor-divider must be used to measure voltages greater than 1.8V.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer Typical Operating Circuit OPTIONAL MARGINING SUPPORT FOR CHANNELS 0–11 (UP TO 3) DS4424 I2C 4-CHANNEL CURRENT DAC (I2C ADDRESSES 20h, 60h, A0h) POWER SUPPLY OPTIONAL DS75LV I2C TEMP SENSOR (I2C ADDRESSES 90/92/94/96h) OPTIONAL REMOTE TEMP SENSORS (UP TO 4) PSEN0– PSEN3 MSDA MSCL IN OUT LOAD EN VDDA ONLY REQUIRED IF THE MONITORED VOLTAGE IS > 1.8V RS0– RS3 3.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer Package Information Ordering Information PART TEMP RANGE PIN-PACKAGE MAX34460ETM+ -40NC to +85NC 48 TQFN-EP* MAX34460ETM+T -40NC to +85NC 48 TQFN-EP* +Denotes a lead(Pb)-free/RoHS-compliant package. *EP = Exposed pad. T = Tape and reel. Maxim Integrated For the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages.
MAX34460 PMBus 12-Channel Voltage Monitor and Sequencer Revision History REVISION NUMBER REVISION DATE 0 9/12 Initial release 1 11/13 Updated the Absolute Maximum Ratings section; added VDD rise time and trace impedance to the Recommended Operating Conditions table; corrected errors in the 24h and 26h 7-bit slave address of Table 2; added the Protecting Input Pins section DESCRIPTION PAGES CHANGED — 8, 19, 62 Maxim Integrated cannot assume responsibility for use of any circuitry other than circuit