EVALUATION KIT AVAILABLE MAX34446 PMBus Power-Supply Data Logger General Description The MAX34446 data logger for power supplies can monitor voltages for overvoltage and undervoltage, as well as for overcurrent conditions and overtemperature conditions. The device constantly checks for userprogrammable thresholds; when these thresholds are exceeded, the device logs the recent real-time operating conditions in nonvolatile flash memory. The device can monitor up to four voltages or currents, and can monitor three temperature sensors. See the Typical Application Circuit/Block Diagram for more details. Applications Base Stations Industrial Controls Network Switches/Routers Features SVoltage, Current, and Temperature Measurement and Threshold Excursion Detection SSupports Up to Four Voltage or Current Measurements SSupports Up to Three Temperature Sensors: Two Remote Diodes Plus an Internal Sensor SCalculates Power Consumption SDifferential 12-Bit ADC SPMBus™-Compliant Control Interface SPower-Good Outputs SIndividual Fault Outputs SOn-Board Nonvolatile Fault Logging and Default Configuration Setting Servers SI2C/SMBus-Compatible Serial Bus with Bus Timeout Function Smart Grid Network Systems SNo External Clocking Required S2.7V to 5.5V Supply Voltage SLow Power Consumption Ordering Information appears at end of data sheet. S-40NC to +105NC Temperature Range S40-Pin TQFN (6mm x 6mm) Package Typical Application Circuit/Block Diagram appears at end of data sheet. PMBus is a trademark of SMIF, Inc. For related parts and recommended products to use with this part, refer to: www.maximintegrated.com/MAX34446.related For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com. 19-5879; Rev 2; 9/12 MAX34446 PMBus Power-Supply Data Logger ABSOLUTE MAXIMUM RATINGS VDD to VSS............................................................-0.3V to +5.5V RS-[5:0] to VSS......................................................-0.3V to +0.3V All other pins except REG18 and REG25 relative to VSS.......................... -0.3V to (VDD + 0.3V)* Continuous Power Dissipation (TA = +70NC) TQFN (derate 35.7mW/NC above +70C).................2857.1mW Operating Temperature Range......................... -40NC to +105NC Storage Temperature Range............................. -55NC to +125NC Lead Temperature (soldering, 10s).................................+300NC Soldering Temperature (reflow).......................................+260NC *Subject to not exceeding +5.5V. Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. RECOMMENDED OPERATING CONDITIONS (TA = -40NC to +105NC, unless otherwise noted.) PARAMETER SYMBOL MAX UNITS 2.7 5.5 V VIH 0.7 x VDD VDD + 0.3 V VIL 0 0.3 x VDD V VDD Operating Voltage VDD Input Logic-High Input Logic-Low CONDITIONS (Note 1) MIN TYP Input Logic-High: SCL, SDA VI2C_IH 2.7V P VDD P 3.6V (Note 1) 2.1 VDD + 0.3 V Input Logic-Low: SCL, SDA VI2C_IL 2.7V P VDD P 3.6V (Note 1) 0 +0.8 V DC ELECTRICAL CHARACTERISTICS (VDD = 2.7V to 5.5V, TA = -40NC to +105NC, unless otherwise noted. Typical values are at VDD = 3.3V, TA = +25NC.) PARAMETER Supply Current Brownout Voltage SYMBOL ICPU CONDITIONS (Note 2) VBO Monitors VDD (Note 1) Monitors VDD (Note 1) Internal System Clock fMOSC +25NC P TA P +85NC fERR:MOSC -40NC P TA P +25NC -20NC P TA P +105NC Output Logic-Low VOL1 IOL = 4mA (Note 1) Output Logic-High VOH1 IOH = -2mA (Note 1) Maxim Integrated IPU MAX VPIN = VSS, VDD = 3.3V 2.40 2.46 2.55 V 30 mV 4.0 MHz -3 +2 -6.5 +1.6 -4 +2.5 0.4 VDD 0.5 38 UNITS mA 8 VBOH Pullup Current TYP 3.0 IPROGRAM Brownout Hysteresis System Clock Error (Note 3) MIN % V V 55 107 FA 2 MAX34446 PMBus Power-Supply Data Logger DC ELECTRICAL CHARACTERISTICS (continued) (VDD = 2.7V to 5.5V, TA = -40NC to +105NC, unless otherwise noted. Typical values are at VDD = 3.3V, TA = +25NC.) PARAMETER SYMBOL CONDITIONS MIN TYP 1.225 ADC Full-Scale Voltage TA = +25NC 1.22 ADC Full-Scale Temperature Drift TA = -40NC to +105NC -0.6 ADC Measurement Resolution VLSB ADC Integral Nonlinearity ADC Offset RIN INL Remote Temperature Measurement Error (MAX3446 Error Only) 1.23 V % FV 12 Bits 15 MI (Note 4) Q8 VOFFSET Internal Temperature Measurement Error UNITS +0.6 300 ADC Bit Resolution RS+ Input Resistance MAX TA = -40NC to +85NC -3 +3 TA = -40NC to +105NC -3.5 +3.5 TA = 0NC to +60NC, TDIODE = +60NC to +120NC -1.5 +1.5 TA = 0NC to +60NC, TDIODE = -45NC to +120NC -1.75 +1.75 TA = -40NC to +105NC, TDIODE = -45NC to +120NC -3.5 +3.5 SYNC Frequency Range 20 SYNC Duty Cycle 40 50 LSB LSB Q2 NC NC 500 kHz 60 % Store Default All Time 37 ms Nonvolatile Log Write Time 37 ms Nonvolatile Log Delete Time 775 ms Nonvolatile Log Overwrite Time 40 Flash Endurance Data Retention NFLASH TA = +50NC 20,000 TA = +50NC 100 Current or Voltage Sample Rate Temperature Sample Rate Per temperature sensor Device Startup Time Measurement from POR until monitoring begins Maxim Integrated ms Write Cycles Years 500 Fs 1000 ms 12 ms 3 MAX34446 PMBus Power-Supply Data Logger I2C/SMBus INTERFACE ELECTRICAL CHARACTERISTICS (VDD = 2.7V to 5.5V, TA = -40NC to +105NC, unless otherwise noted. Typical values are at VDD = 3.3V, TA = +25NC.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS 100 kHz SCL Clock Frequency fSCL 10 Bus Free Time Between STOP and START Conditions tBUF 4.7 Fs Hold Time (Repeated) START Condition tHD:STA 4.0 Fs Low Period of SCL tLOW 4.7 Fs High Period of SCL tHIGH 4.0 Fs Receive 0 Transmit 300 Data Hold Time tHD:DAT ns Data Setup Time tSU:DAT 100 ns START Setup Time tSU:STA 4.7 Fs SDA and SCL Rise Time tR 300 ns SDA and SCL Fall Time tF 300 ns STOP Setup Time Clock Low Timeout tSU:STO 4.0 tTO 25 Fs 35 ms Note 1: All voltages are referenced to ground (VSS). Currents entering the device are specified as positive, and currents exiting the device are specified as negative. Note 2: This does not include pin input/output currents. Note 3: Guaranteed by design; not production tested. Note 4: ADC has no missing codes. I2C/SMBus Timing SDA tBUF tF tLOW tHD:STA tSP SCL tHD:STA tHIGH tR tHD:DAT STOP START tSU:STA tSU:STO tSU:DAT REPEATED START NOTE: TIMING IS REFERENCED TO VIL(MAX) AND VIH(MIN). Maxim Integrated 4 MAX34446 PMBus Power-Supply Data Logger Typical Operating Characteristics (VDD = 2.7V to 5.5V, TA = -40NC to +105NC, unless otherwise noted. Typical values are at VDD = 3.3V, TA = +25NC.) SUPPLY CURRENT vs. TEMPERATURE SUPPLY CURRENT vs. SUPPLY VOLTAGE 3.6 3.8 3.6 3.4 3.2 3.2 IDD (mA) 3.4 3.0 2.8 2.6 2.8 2.2 2.0 -40 -20 0 20 40 60 80 100 120 2.0 2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5 TEMPERATURE (°C) VDD (V) IDD vs. TIME DURING A NONVOLATILE LOG WRITE DUE TO LOG PIN (VDD = 3.3V, ALL CHANNELS ENABLED, SYNC PIN ACTIVE AT 100kHz) IDD vs. TIME DURING A NONVOLATILE MFR_TIME_COUNT WRITE DUE TO ENABLE PIN (VDD = 3.3V, ALL CHANNELS ENABLED, SYNC PIN ACTIVE AT 100kHz) MAX34446 toc03 5V/div LOG 0V MAX34446 toc04 2V/div 0V 2V/div 0V 1mA/div IDD 1mA/div 0mA 2ms/div Maxim Integrated TA = +25°C 2.4 2.2 0mA 3.0 2.6 VDD = 3.3V 2.4 MAX34446 toc02 3.8 IDD (mA) 4.0 MAX34446 toc01 4.0 ENABLE PIN FAULT6 IDD 2ms/div 5 MAX34446 PMBus Power-Supply Data Logger VSS REG18 FAULT3 PG2 PG1 FAULT2 FAULT1 PG0 FAULT0 TOP VIEW REG25 Pin Configuration 30 29 28 27 26 25 24 23 22 21 SDA 31 20 PG3 SCL 32 19 FAULT4 A0 33 18 N.C. 17 FAULT5 LOG 34 ENABLE 35 16 SYNC MAX34446 15 FAULT6 VSS 36 14 N.C. A1 37 N.C. 38 13 RST EP + RS-5 39 12 RS-2 11 RS+2 7 8 9 10 VDD RS-1 6 RS-0 RS+4 5 RS+1 VSS 4 RS+0 3 RS-3 2 RS+3 1 RS-4 RS+5 40 TQFN (6mm × 6mm × 0.75mm) Pin Description PIN NAME FUNCTION 1 RS-4 Ground Reference for ADC4 Remote Thermal Diode Voltage Measurement 2, 21, 36 VSS Digital-Supply Return Node 3 RS+4 Remote Thermal Diode ADC4 Sense Input, Measurement Relative to RS-4 4 RS-3 Ground Reference for ADC3 Voltage or Current Measurement 5 RS+3 ADC3 Voltage or Current Sense Input, Measurement Relative to RS-3 6 RS+0 ADC0 Voltage or Current Sense Input, Measurement Relative to RS-0 7 RS-0 Ground Reference for ADC0 Voltage or Current Measurement 8 RS+1 ADC1 Voltage or Current Sense Input, Measurement Relative to RS-1 9 VDD Input Supply Voltage. Bypass VDD to VSS with a 0.1FF capacitor. 10 RS-1 Ground Reference for ADC1 Voltage or Current Measurement 11 RS+2 ADC2 Voltage or Current Sense Input, Measurement Relative to RS-2 12 RS-2 Ground Reference for ADC2 Voltage or Current Measurement 13 RST Active-Low Reset Input/Output 14, 18, 38 N.C. No Connection. Do not connect any signal to these pins. 15 FAULT6 Maxim Integrated Active-Low, Open-Drain Fault Output for Internal Temperature Sensor 6 MAX34446 PMBus Power-Supply Data Logger Pin Description (continued) PIN NAME FUNCTION 16 SYNC Push-Pull Output Clock. This clock changes between two programmable frequencies based on state of power good. High impedance when disabled and when ENABLE is low. 17 FAULT5 Active-Low, Open-Drain Fault Output for Remote Diode Temperature Sensor Connected to ADC5 19 FAULT4 Active-Low, Open-Drain Fault Output for Remote Diode Temperature Sensor Connected to ADC4 20 PG3 22 REG18 Regulator for Low-Voltage Digital Circuitry. Bypass REG18 to VSS with 1FF and 10nF capacitors. Do not connect other circuitry to this pin. 23 FAULT3 Active-Low, Open-Drain Fault Output for Voltage or Current Fault on ADC3 24 PG2 Power-Good Output for ADC2. Active-high push-pull or open-drain output. 25 FAULT2 Active-Low, Open-Drain Fault Output for Voltage or Current Fault on ADC2 26 PG1 Power-Good Output for ADC1. Active-high push-pull or open-drain output. 27 FAULT1 Active-Low, Open-Drain Fault Output for Voltage or Current Fault on ADC1 28 PG0 Power-Good Output for ADC0. Active-high push-pull or open-drain output. 29 REG25 Regulator for Analog Circuitry. Bypass REG25 to VSS with 1FF and 10nF capacitors. Do not connect other circuitry to this pin. 30 FAULT0 Active-Low, Open-Drain Fault Output for Voltage or Current Fault on ADC0 31 SDA I2C/SMBus-Compatible Bidirectional Data Line. Open-drain output. 32 SCL I2C/SMBus-Compatible Clock 33 A0 34 LOG Active-Low Force Nonvolatile Logging. Active-low input with an internal 55FA pullup. A falling edge on this pin causes the device to log the most recent set of collected data into the nonvolatile memory. This pin has a 100Fs deglitch filter. Leave open circuit if not needed. 35 ENABLE Device Enable. Connect to VDD to enable the device. This pin has a 100Fs deglitch filter. When low, no monitoring or data logging occurs, the PGn outputs are forced low, and the FAULTn outputs are high impedance. On the falling edge of ENABLE, the device attempts to write MFR_TIME_COUNT into nonvolatile memory. 37 A1 Power-Good Output for ADC3. Active-high push-pull or open-drain output. I2C/SMBus Address Select Bit 0 I2C/SMBus Address Select Bit 1 39 RS-5 Ground Reference for ADC5 Remote Thermal Diode Voltage Measurement 40 RS+5 Remote Thermal Diode ADC5 Sense Input, Measurement Relative to RS-5 — EP Exposed Pad (Bottom Side of Package). Connect EP to VSS. Note: All pins except VDD, VSS, REG18, REG25, the ADC pins, and the exposed pad are high impedance with a 55µA pullup during device power-up and reset. After device reset, the weak pullup is removed and the pin is configured as an input or output. Maxim Integrated 7 MAX34446 PMBus Power-Supply Data Logger Table 1. PMBus Command Codes CODE COMMAND NAME TYPE PAGE 0–3 PAGE 4, 5, 6 PAGE 255 (NOTE 1) NO. OF BYTES LOCKED (NOTE 2) FLASH STORED (NOTE 3) DEFAULT VALUE (NOTE 3) 00h PAGE R/W Byte R/W R/W R/W 1 N N 00h 03h CLEAR_FAULTS Send Byte W W W 0 Y N — 10h WRITE_PROTECT R/W Byte R/W R/W R/W 1 Y N 00h 11h STORE_DEFAULT_ALL Send Byte W W W 0 Y N — 12h RESTORE_DEFAULT_ALL Send Byte W W W 0 Y N — 19h CAPABILITY Read Byte R R R 1 N FIXED 00h 20h VOUT_MODE Read Byte R R R 1 N FIXED 40h 2Ah VOUT_SCALE_MONITOR R/W Word R/W — — 2 Y Y 7FFFh 38h IOUT_CAL_GAIN R/W Word R/W — — 2 Y Y 0000h 40h VOUT_OV_FAULT_LIMIT R/W Word R/W — — 2 Y Y 7FFFh 42h VOUT_OV_WARN_LIMIT R/W Word R/W — — 2 Y Y 7FFFh 43h VOUT_UV_WARN_LIMIT R/W Word R/W — — 2 Y Y 0000h 44h VOUT_UV_FAULT_LIMIT R/W Word R/W — — 2 Y Y 0000h 46h IOUT_OC_WARN_LIMIT R/W Word R/W — — 2 Y Y 7FFFh 4Ah IOUT_OC_FAULT_LIMIT R/W Word R/W — — 2 Y Y 0000h 4Fh OT_FAULT_LIMIT R/W Word — R/W — 2 Y Y 0000h 51h OT_WARN_LIMIT R/W Word — R/W — 2 Y Y 7FFFh 5Eh POWER_GOOD_ON R/W Word R/W — — 2 Y Y 0000h 5Fh POWER_GOOD_OFF R/W Word R/W — — 2 Y Y 0000h 78h STATUS_BYTE Read Byte R R R 1 N N 00h 79h STATUS_WORD Read Word R R R 2 N N 0000h 7Ah STATUS_VOUT Read Byte R — — 1 N N 00h 7Eh STATUS_CML Read Byte R R R 1 N N 00h 80h STATUS_MFR_SPECIFIC Read Byte R R — 1 N N 00h 8Bh READ_VOUT Read Word R — — 2 N N 0000h 8Ch READ_IOUT Read Word R — — 2 N N 0000h 8Dh READ_TEMPERATURE_1 Read Word — R — 2 N N 0000h 96h READ_POUT Read Word R — — 2 N N 0000h 98h PMBUS_REVISION Read Byte R R R 1 N FIXED 11h 99h MFR_ID Read Byte R R R 1 N FIXED 4Dh 9Ah MFR_MODEL Read Byte R R R 1 N FIXED 54h 9Bh MFR_REVISION Read Word R R R 2 N FIXED (Note 4) 9Ch MFR_LOCATION Block R/W R/W R/W R/W 8 Y Y (Note 5) 9Dh MFR_DATE Block R/W R/W R/W R/W 8 Y Y (Note 5) 9Eh MFR_SERIAL Block R/W R/W R/W R/W 8 Y Y (Note 5) D1h MFR_MODE R/W Word R/W R/W R/W 2 Y Y 0000h D4h MFR_VOUT_PEAK R/W Word R/W — — 2 Y N 0000h D5h MFR_IOUT_PEAK R/W Word R/W — — 2 Y N 0000h D6h MFR_TEMPERATURE_PEAK R/W Word — R/W — 2 Y N 8000h Maxim Integrated 8 MAX34446 PMBus Power-Supply Data Logger Table 1. PMBus Command Codes (continued) CODE COMMAND NAME TYPE PAGE 0–3 PAGE 4, 5, 6 PAGE 255 (NOTE 1) NO. OF BYTES LOCKED (NOTE 2) FLASH STORED (NOTE 3) DEFAULT VALUE (NOTE 3) D7h MFR_VOUT_MIN R/W Word R/W — — 2 Y N 7FFFh D9h MFR_FAULT_RESPONSE R/W Byte R/W R/W — 1 Y Y 00h DAh MFR_FAULT_RETRY R/W Word R/W R/W — 2 Y Y 0000h DBh MFR_PG_DELAY R/W Word R/W — — 2 Y Y 0000h DCh MFR_NV_FAULT_LOG Block Read R R R 255 Y Y (Note 6) DDh MFR_TIME_COUNT Block Read R/W R/W R/W 4 Y Y (Note 7) E0h MFR_POUT_PEAK R/W Word R/W — — 2 Y N 0000h E1h MFR_POUT_AVG R/W Word R/W — — 2 Y N 0000h E2h MFR_IOUT_AVG R/W Word R/W — — 2 Y N 0000h E3h MFR_TEMPERATURE_AVG R/W Word — R/W — 2 Y N 0000h EFh MFR_SYNC_CONFIG R/W Word R/W R/W R/W 2 Y Y 0000h Note 1: Common commands are shaded. Access through any page results in the same device response. Note 2: If the device is locked, only the commands listed with “N” can be read. All other commands return FFh if read. Only the PAGE and MFR_SERIAL commands can be written to. The device unlocks if the upper 4 bytes of MFR_SERIAL match the data written to the device. Note 3: In the Flash Stored column, an “N” indicates that this parameter is not stored in flash memory when the STORE_DEFAULT_ALL command is executed and the value shown in the Default Value column is automatically loaded upon power-on reset or when the RST pin is asserted. A “Y” in the Flash Stored column indicates that the currently loaded value in this parameter is stored in flash memory when the STORE_DEFAULT_All command is executed and is automatically loaded upon poweron reset or when the RST pin is asserted and the value shown in the Default Value column is the value when shipped from the factory. “FIXED” in the Flash Stored column means this value is fixed at the factory as a ROM value and cannot be changed. Note 4: The factory-set default value that contains the device revision numbers. Note 5: The factory-set default value for this 8-byte block is 3130313031303130h. Note 6: The factory-set default value for the complete block of the MFR_NV_FAULT_LOG is FFh. Note 7: The factory-set default value for the complete block is 00h. Detailed Description The MAX34446 data logger for power supplies can monitor voltages for overvoltage and undervoltage, as well as for overcurrent conditions and overtemperature conditions. The device constantly checks for userprogrammable thresholds; when these thresholds are Maxim Integrated exceeded, the device logs the recent real-time operating conditions in nonvolatile flash memory. The device can monitor up to four voltages or currents, and can monitor three temperature sensors. See the Typical Application Circuit/Block Diagram for more details. 9 MAX34446 PMBus Power-Supply Data Logger Address Select Table 2. PMBus/SMBus Serial-Port Address On device power-up or reset, the device samples the A0 and A1 pins to determine the PMBus/SMBus serial-port address. See Table 2. 7-BIT SLAVE ADDRESS A1 A0 100kI to VSS 100kI to VSS 100kI to VDD 0010 010 (24h) 100kI to VDD 100kI to VSS 100kI to VDD 0010 100 (28h) SMBus/PMBus Operation 0010 011 (26h) The device implements the PMBus command structure using the SMBus format. The structure of the data flow between the host and the slave is shown below for several different types of transactions. Data is sent most significant bit (MSB) first. 0010 101 (2Ah) 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 1 8 1 8 1 1 R A DATA BYTE LOW A DATA BYTE HIGH NA P READ BYTE FORMAT 1 7 1 1 8 1 1 7 1 1 8 1 1 S SLAVE ADDRESS W A COMMAND CODE A Sr SLAVE ADDRESS R A DATA BYTE NA P 1 8 1 8 1 8 1 1 A COMMAND CODE A DATA BYTE LOW A DATA BYTE HIGH A P WRITE WORD FORMAT 1 7 S SLAVE ADDRESS 1 W WRITE BYTE FORMAT 1 7 1 1 8 1 8 1 1 S SLAVE ADDRESS W A COMMAND CODE A DATA BYTE A P 1 8 1 1 A COMMAND CODE A P SEND BYTE FORMAT 1 7 S SLAVE ADDRESS Maxim Integrated 1 W KEY: S = START Sr = REPEATED START P = STOP W = WRITE BIT (0) R = READ BIT (1) A = ACKNOWLEDGE (0) NA = NOT ACKNOWLEDGE (1) SHADED BLOCK = SLAVE TRANSACTION 10 MAX34446 PMBus Power-Supply Data Logger Group Command data stream. All the devices addressed during this transaction wait for the host to issue a STOP before beginning to respond to the 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 Group Command Write Format SLAVE ADDRESS 1, COMMAND BYTE, AND DATA WORD FOR DEVICE 1 1 7 S SLAVE ADDRESS 1 W 1 8 A COMMAND CODE 1 8 A DATA BYTE LOW 1 8 1 A DATA BYTE HIGH A UUU SLAVE ADDRESS 2, COMMAND BYTE, AND DATA BYTE FOR DEVICE 2 1 7 1 1 8 1 8 1 Sr SLAVE ADDRESS W A COMMAND CODE A DATA BYTE A KEY: UUU S = START Sr = REPEATED START SLAVE ADDRESS 3 AND SEND BYTE FOR DEVICE 3 1 7 1 1 8 1 Sr SLAVE ADDRESS W A COMMAND CODE A P = STOP W = WRITE BIT (0) UUU A = ACKNOWLEDGE (0) SHADED BLOCK = SLAVE TRANSACTION UUU SLAVE ADDRESS N, COMMAND BYTE, AND DATA WORD FOR DEVICE N 1 7 Sr SLAVE ADDRESS 1 W 1 8 A COMMAND CODE 1 8 A DATA BYTE LOW Addressing The device responds to receiving its fixed slave address by asserting an acknowledge (ACK) on the bus. The device does not respond to a general call address; it only responds when it receives its fixed slave address. 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: 1) Ignores the command. 2) Sets the CML bit in STATUS_BYTE. Maxim Integrated 1 8 1 1 A DATA BYTE HIGH A P 3) Sets the CML bit in STATUS_WORD. 4) Sets the DATA_FAULT bit in STATUS_CML. Host Sends or Reads Too Few Bytes For each supported command, the device expects a fixed number of bytes to be written or read from the device. If for any reason fewer than the expected number of bytes is written to or read from the device, the device completely ignores the command and takes no action. Host Sends Too Many Bytes or Bits For each supported command, the device expects a fixed number of bytes to be written to the device. If for 11 MAX34446 PMBus Power-Supply Data Logger any reason more than the expected number of bytes or bits is written to the device, the device does the following: 2) Sets the CML bit in STATUS_BYTE. 1) Ignores the command. 4) Sets the DATA_FAULT bit in STATUS_CML. 2) Sets the CML bit in STATUS_BYTE. 3) Sets the CML bit in STATUS_WORD. 4) Sets the DATA_FAULT bit in STATUS_CML. Host Reads Too Many Bytes or Bits 3) Sets the CML bit in STATUS_WORD. Host Reads from a Write-Only Command When a read request is issued to a write-only command (CLEAR_FAULTS, STORE_DEFAULT_ALL, and RESTORE_DEFAULT_ALL), the device does the following: For each supported command, the device expects a fixed number of bytes to be read from the device. If for any reason more than the expected number of bytes or bits is read from the device, the device does the following: 1) ACKs the address byte. 1)Sends all ones (FFh) as long as the host keeps acknowledging. 4) Sets the CML bit in STATUS_BYTE. 2) Sets the CML bit in STATUS_BYTE. 3) Sets the CML bit in STATUS_WORD. 4) Sets the DATA_FAULT bit in STATUS_CML. Host Sends Improperly Set Read Bit in the Slave Address Byte If the device receives the R/W bit in the slave address set to one immediately preceding the command code, the device does the following: 2)Sends all ones (FFh) as long as the host keeps acknowledging. 3) Sets the CML bit in STATUS_BYTE. 4) Sets the CML bit in STATUS_WORD. 5) Sets the DATA_FAULT bit in STATUS_CML. Unsupported Command Code Received If the host sends the device a command code that it does not support, or if the host sends a command code that is not supported by the current PAGE setting, the device does the following: 1) Ignores the command. 2) Sets the CML bit in STATUS_BYTE. 3) Sets the CML bit in STATUS_WORD. 4) Sets the COMM_FAULT bit in STATUS_CML. Invalid Data Received The device checks the PAGE and WRITE_PROTECT command codes for valid data. If the host writes a data value that is invalid, the device does the following: Maxim Integrated 3)Sends all ones (FFh) as long as the host keeps acknowledging. 5) Sets the CML bit in STATUS_WORD. 6) Sets the DATA_FAULT bit in STATUS_CML. Host Writes to a Read-Only Command When a write request is issued to a read-only command, the device does the following: 1) Ignores the command. 2) Sets the CML bit in STATUS_BYTE. 3) Sets the CML bit in STATUS_WORD. 4) Sets the COMM_FAULT bit in STATUS_CML. 1) ACKs the address byte. 1) Ignores the command. 2) Ignores the command. SMBus Timeout If during an active SMBus communication sequence the SCL signal is held low for greater than the timeout duration (tTO), the device terminates the sequence and resets the serial bus. It takes no other action. No status bits are set. PMBus Operation From a software perspective, the device appears as a PMBus device capable of executing a subset of PMBus commands. A PMBus 1.1-compliant device uses the SMBus version 1.1 for transport protocol and responds to the SMBus slave address. In this data sheet, the term SMBus is used to refer to the electrical characteristics of the PMBus communication using the SMBus physical layer. The term PMBus is used to refer to the PMBus command protocol. The device employs a number of standard SMBus protocols to program voltage warning/faults thresholds, read monitored data, and provide access to all manufacturer-specific commands. The device supports the group command. The group command is used to send commands to more than one PMBus device. It is not required that all the devices 12 MAX34446 PMBus Power-Supply Data Logger receive the same command. However, no more than one command can be sent to any one device in one group command packet. The group command must not be used with commands that require receiving devices to respond with data, such as the STATUS_BYTE command. When the device receives a command through this protocol, it immediately begins execution of the received command after detecting the STOP condition. PMBus commands, refer to Part II of the PMBus specification available at www.PMBus.org. The supported PMBus commands and the corresponding device behavior are described in this document. All data values are represented in DIRECT format, unless otherwise stated. Whenever the PMBus specification refers to the PMBus device, it is referring to the MAX34446. While the command can call for turning on or turning off the PMBus device, the MAX34446 always remains on to continue communicating with the PMBus master. The device supports the PAGE command and uses it to select which individual channel to access. When a data word is transmitted, the lower order byte is sent first and the higher order byte is sent last. Within any byte, the most significant bit (MSB) is sent first and the least significant bit (LSB) is sent last. Data Format Voltage data for commanding or reading the output voltage or related parameters (such as the overvoltage threshold) is presented in DIRECT format. DIRECT format data is a 2-byte, two’s complement binary value. DIRECT format data can be used with any command that sends or reads a parametric value. The DIRECT format uses an equation and defined coefficients to calculate the desired values. Table 3 shows the coefficients used by the device. PMBus Protocol Support The device supports a subset of the commands defined in the PMBus Power System Management Protocol Specification Part II - Command Language, Revision 1.1. For detailed specifications and the complete list of Table 3. PMBus Command Code Coefficients PARAMETER UNITS RESOLUTION MAX m b R Voltage VOUT_OV_FAULT_LIMIT VOUT_UV_FAULT_LIMIT POWER_GOOD_ON POWER_GOOD_OFF READ_VOUT MFR_VOUT_PEAK MFR_VOUT_MIN mV 1 32,767 1 0 0 Voltage Scaling VOUT_SCALE_MONITOR — 1/32,767 1 32,767 0 0 Current IOUT_OC_FAULT_LIMIT READ_IOUT MFR_IOUT_PEAK MFR_IOUT_AVG mA 1 32,767 1 0 0 IOUT_CAL_GAIN mI 0.1 3276.7 1 0 1 OT_FAULT_LIMIT READ_TEMPERATURE_1 MFR_TEMPERATURE_PEAK MFR_TEMPERATURE_AVG NC 0.01 327.67 1 0 2 Timing MFR_FAULT_RETRY MFR_PG_DELAY ms 1 32,767 1 0 0 Power READ_POUT MFR_POUT_PEAK MFR_POUT_AVG W 1 32,767 1 0 0 Current Scaling Temperature Maxim Integrated COMMANDS 13 MAX34446 PMBus Power-Supply Data Logger Interpreting Received DIRECT Format Values The host system uses the following equation to convert the value received from the PMBus device—in this case, the MAX34446—into a reading of volts, degrees Celsius, or other units as appropriate: X = (1/m) x (Y x 10-R - b) where X is the calculated, real world value in the appropriate units (V, NC, etc.); m is the slope coefficient; Y is the 2-byte, two’s complement integer received from the PMBus device; b is the offset; and R is the exponent. Sending a DIRECT Format Value To send a value, the host must use the below equation to solve for Y: Y = (mX + b) x 10R where Y is the 2-byte, two’s complement integer to be sent to the unit; m is the slope coefficient; X is the real world value, in units such as volts, to be converted for transmission; b is the offset; and R is the exponent. The following example demonstrates how the host can send and retrieve values from the device. If the host received a value of 0D89h on a READ_VOUT command, this is equivalent to: X = (1/1) x (0D89h x 10-(-0) – 0) = 3465mV = 3.465V with READ_VOUT (8Bh) coefficients m = 1, b = 0, and R = 0 (see Table 3). All voltage-related parameters of PMBus devices are reported as positive values. It is up to the system to know that a particular output is negative if that is of interest to the system. All output voltage-related commands use 2 data bytes. Maxim Integrated Fault Management and Reporting Faults are reported in the various status registers and, if enabled with the MFR_FAULT_RESPONSE command, faults can also be indicated on the associated FAULTn output. See the individual command sections for more details. Faults and warnings that are latched in the status registers are cleared when any one of the following conditions occurs: • A CLEAR_FAULTS command is received. • The RST pin is toggled low. • Bias power to the device is removed and then reapplied. The device responds to fault conditions according to the manufacturer fault response command (MFR_FAULT_RESPONSE). This command byte determines how the device should respond to each particular fault. 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 1 for a complete list. 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 and MFR_SERIAL commands can be written; all other commands that are written are ignored. When MFR_SERIAL is written and the upper 4 bytes match the internally flashstored value, the device unlocks and remains unlocked until the LOCK bit in MFR_MODE is activated once again. The LOCKED status bit in STATUS_MFR_SPECIFIC is always available to indicate whether the device is locked or unlocked. 14 MAX34446 PMBus Power-Supply Data Logger Voltage/Current Monitoring Temperature Sensor Operation ADC inputs 0 to 3 can be independently configured to monitor either voltage or current. The device defaults to monitoring voltage on the ADC0 to ADC3 inputs, but if the IOUT_OC_FAULT_LIMIT command is configured with a positive nonzero value, the device instead monitors current on the associated ADC input. When an ADC input is configured to monitor voltage, all current related commands (like READ_IOUT) are invalid on the associated page and, likewise when an ADC input is configured to monitor current, all voltage-related commands are invalid and the PGn outputs are forced high impedance. The device can monitor up to three different temperature sensors, two external remote diode temperature sensors plus its own internal temperature sensor. The device defaults to having the temperature sensors disabled, but if the OT_FAULT_LIMIT command is configured with a positive nonzero value, the temperature sensor is enabled on the associated page. The device reads one of the enabled temperature sensors once per second. Hence, if only one temperature sensor is enabled, it is read every second. If all three temperature sensors are enabled, each sensor is read once every 3 seconds. Power Calculation Each time the device attempts to read a temperature sensor, it checks for faults. For the remote diode, a fault is defined as a reading greater than +160NC or less than -60NC. For the internal temperature sensor, a fault is defined as a reading greater than +130NC or less than -60NC. Temperature sensor faults are reported by setting the temperature reading to 7FFFh. A temperature sensor fault results in the setting of the TEMPERATURE bit in STATUS_BYTE and STATUS_WORD. No bits are set in STATUS_MFR_SPECIFIC. The device can be configured to calculate power consumption. The READ_POUT, MFR_POUT_PEAK, and MFR_POUT_AVG commands only contain valid data when the device is configured as shown below. The device can calculate power on up to two power nodes by using 4 channels of the ADC: two for voltage measurement and two for current measurement. To measure power, ADC0 and ADC1 must be coupled together and ADC2 and ADC3 must be coupled together. Since the PMBus page alignment is assigned based on the ADC input, power is reported in both pages of the associated coupled voltage/current pair. Power Measurement 1 (Page 0 or 1) Power Measurement 2 (Page 2 or 3) Maxim Integrated The remote diode temperature sensor can support either npn or pnp transistors. The device automatically cancels the series resistance that can affect remote diodes that are located far from the device. ADC0 = Voltage Measurement (Page 0) ADC1 = Current Measurement (Page 1) ADC2 = Voltage Measurement (Page 2) ADC3 = Current Measurement (Page 3) 15 MAX34446 PMBus Power-Supply Data Logger RESET COMPLETE AND ENABLE PIN HIGH DISABLE WRITES TO MFR_NV_FAULT_LOG IF FAULT_EN ≠ 0X, ASSERT FAULTn PIN FORCE PGn PINS LOW ON ALL CHANNELS CONFIGURED TO MONITOR VOLTAGE (OTHER PGn PINS ARE HIGH IMPEDANCE) MEASURE THE VOLTAGE/CURRENT/TEMPERATURE ON VOLTAGE CHANNELS, IS THE MEASURED VOLTAGE > POWER_GOOD_ON? YES NO SET PGn PIN HIGH AFTER MFR_PG_DELAY IS THE MEASURED PARAMETER WITHIN FAULT LIMITS? (ALSO INCLUDES WARNING LIMITS IF FAULT_EN = 11) NO YES DEASSERT THE FAULTn PIN ENABLE WRITES TO MFR_NV_FAULT_LOG REGULAR PARAMETER MONITORING BEGINS Figure 1. PGn and FAULTn Output After a Channel is Enabled Fault Response When a Channel is Enabled a fault/warning status bit or write a nonvolatile fault log when a fault/warning occurs, the channel must first pass this particular fault or warning. Whenever a channel (voltage, current, or temperature) is enabled (VDD cycle, or hardware or software reset, or by PMBus command) the channel’s FAULTn signal is asserted if the FAULT_EN bits in MFR_FAULT_RESPONSE are set so that the device responds to a fault or warning. If enabled, the FAULTn pin is not released until all measurements pass. Also, prior to being allowed to set Figure 1 describes the steps that the MAX34446 takes to monitor a channel after the channel is enabled. Figure 2 explains how the MAX34446 responds after a channel is enabled and as faults and warnings pass and fail. Figure 2 shows a voltage channel and overvoltage faults and warnings, but these same steps apply to other monitored parameters as well. Maxim Integrated 16 MAX34446 PMBus Power-Supply Data Logger ADC INPUT A D VOUT_OV_FAULT_LIMIT 2% HYSTERESIS E K F B C J G VOUT_OV_WARN_LIMIT I 2% HYSTERESIS H FAULTn NOTE 1: POINTS A THROUGH K ARE VOLTAGE SAMPLE POINTS. NOTE 2: MFR_FAULT_RESPONSE = 82h. THE MAX34446 ONLY RESPONDS TO FAULTS. A. B. C. D. E. F. G. H. I. J. K. THE CHANNEL IS ENABLED (POR, ENABLE, OR THROUGH PMBus). FAULTn ASSERTED, NO STATUS BITS SET, NO NV LOG. NO CHANGE. FAULTn IS RELEASED. THE MAX34446 IS NOW ALLOWED TO RESPOND TO VOUT_OV_FAULT_LIMIT EXCURSIONS. FAULTn IS ASSERTED. VOUT_OV_FAULT STATUS IS SET, BUT NOT VOUT_OV_WARN. AN NV LOG IS WRITTEN. NO CHANGE. NO CHANGE. FAULTn IS RELEASED. VOUT_OV_FAULT STATUS CAN BE CLEARED. THE MAX34446 IS NOW ALLOWED TO RESPOND TO VOUT_OV_WARN_LIMIT EXCURSIONS. NO CHANGE. VOUT_OV_WARN STATUS IS SET. FAULTn IS ASSERTED. VOUT_OV_FAULT STATUS IS SET. AN NV LOG IS WRITTEN. Figure 2. Fault Response After a Channel is Enabled System Watchdog Timer were stored to flash and begins normal operation. After the reset, the device also does the following: The device uses an internal watchdog timer that is internally reset every 500Fs. In the event that the device is locked up and this watchdog reset does not occur after 500ms, the device automatically resets. After the reset occurs, the device reloads all configuration values that 1) Sets the NONE OF THE ABOVE bit in STATUS_BYTE. Maxim Integrated 2)Sets the NONE OF THE ABOVE and MFR bits in STATUS_WORD. 3) Sets the WATCHDOG bit in STATUS_MFR_SPECIFIC. 17 MAX34446 PMBus Power-Supply Data Logger PMBus Commands A summary of the PMBus commands supported by the device is described in the following sections. PAGE (00h) The device can monitor up to four remote voltages or currents: up to two remote diode temperature sensors, and an internal temperature sensor using one PMBus (I2C) address. Send the PAGE command with data 0 to 6 to select which voltage or current or temperature sensor is affected by all the following PMBus commands. Not all commands are supported within each page. If an unsupported command is received, the CML status bit is set. Some commands are common, meaning that any selected page has the same effect on and the same response from the device. Set the PAGE to 255 when it is desired that the PMBus commands in Table 1 should apply to all pages at the same time. Table 4. PAGE Commands PAGE (DEC) ASSOCIATED CONTROL 0 Remote Voltage-Divider or Current-Sense Amplifier Connected to ADC0 1 Remote Voltage-Divider or Current-Sense Amplifier Connected to ADC1 2 Remote Voltage-Divider or Current-Sense Amplifier Connected to ADC2 3 Remote Voltage-Divider or Current-Sense Amplifier Connected to ADC3 4 Remote Diode Temperature Sensor Connected to ADC4 5 Remote Diode Temperature Sensor Connected to ADC5 6 Internal Temperature Sensor 7 to 254 255 Maxim Integrated Reserved Applies to All Pages 18 MAX34446 PMBus Power-Supply Data Logger CLEAR_FAULTS (03h) The CLEAR_FAULTS command is used to clear any latched status bits that have been set. This command clears all bits simultaneously. If the fault/warning is still present after the CLEAR_FAULTS command is executed, the status bit is set again. This command is write-only. There is no data byte for this command. WRITE_PROTECT (10h) The WRITE_PROTECT command is used to provide protection against accidental changes to the device’s operating memory. All supported commands can have their parameters read, regardless of the WRITE_PROTECT settings. Table 5 describes the WRITE_PROTECT message content. Table 5. WRITE_PROTECT Command Byte COMMAND BYTE MEANING 80h Disable all writes except the WRITE_PROTECT command. 40h Disable all writes except the WRITE_PROTECT and PAGE commands. 00h Enable writes for all commands (default). Note: No fault or error is generated if the host attempts to write to a protected area. STORE_DEFAULT_ALL (11h) The STORE_DEFAULT_ALL command instructs the device to transfer the device configuration information to the internal flash memory array. Not all information is stored. Only configuration data is stored, not any status, or operational data. If an error occurs during the transfer, the CML bit is set to 1. The device is unresponsive to PMBus commands while transferring the configuration. This command is write-only. There is no data byte for this command. 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. Upon a device power-on reset or device reset through the RST input pin, this command is automatically executed by the device without PMBus action required. This command is write-only. There is no data byte for this command. CAPABILITY (19h) The CAPABILITY command is used to determine some key capabilities of the device. The CAPABILITY command is read-only. Table 6 describes the message content. Table 6. CAPABILITY Command Byte BIT 7 6:5 4 3:0 DESCRIPTION MEANING Packet-Error Checking 0 = PEC not supported. PMBus Speed 00 = Maximum supported bus speed is 100kHz. ALERT 0 = Device does not support ALERT output. Reserved Always returns 0000. Maxim Integrated 19 MAX34446 PMBus Power-Supply Data Logger VOUT_MODE (20h) The VOUT_MODE command is used to report the device’s data format. The device uses the DIRECT format for all the voltage-related commands. The value returned is 40h, indicating DIRECT data format. This command is read-only. If a host attempts to write this command, the CML status bit is asserted. See Table 3 for the m, b, and R values for the various commands. VOUT_SCALE_MONITOR (2Ah) VOUT_SCALE_MONITOR is used in applications where the measured power-supply voltage is not equal to the voltage at the ADC input. For example, if the ADC input expects a 1.0V input for a 12V output, VOUT_SCALE_MONITOR = 1.0V/12V = 0.0833. In applications where the power-supply voltage is greater than the device’s input range, the voltage of the power supply is sensed through a resistive voltage-divider. The resistive voltage-divider reduces or scales the output voltage. The PMBus commands specify the actual power-supply voltages and not the input voltage to the ADC. To allow the device to map between the power-supply voltage (such as 12V) and the voltage at the ADC input, the VOUT_SCALE_MONITOR command is used. The 2 data bytes are in DIRECT format. This value is dimensionless. For example, if the required scaling factor is 0.0833, then VOUT_SCALE_MONITOR should be set to 0AABh (2731/32,767 = 0.0833). See Table 7. USER NOTE: The device’s full-scale ADC voltage is 1.225V. A scaling factor where a 1.0V ADC input represents a nominal 100% voltage level is recommended. Table 7. VOUT_SCALE_MONITOR NOMINAL VOLTAGE LEVEL MONITORED (V) NOMINAL ADC INPUT VOLTAGE LEVEL (V) (SEE USER NOTE) RESISTIVE VOLTAGEDIVIDER RATIO VOUT_SCALE_MONITOR VALUE (HEX) 1.2 1.0 0.833 6AAAh 1.5 1.0 0.667 5555h 1.8 1.0 0.555 470Ah 2.5 1.0 0.4 3333h 3.3 1.0 0.303 26C8h 5 1.0 0.2 1999h 12 1.0 0.0833 0AABh IOUT_CAL_GAIN (38h) The IOUT_CAL_GAIN command is used to set the ratio of the voltage at the ADC input to the sensed current. The units of the IOUT_CAL_GAIN factor are 0.1mI. The 2 data bytes are in DIRECT format. For example, if a 10mI sense resistor is used in conjunction with a 50V/V current sense amplifier, the IOUT_CAL_GAIN should be set to 500mI or 1388h. USER NOTE: The device’s full-scale ADC voltage is 1.225V. The value of the sense resistor and current sense amplifier gain must be scaled appropriately. 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. In response to the VOUT_OV_FAULT_LIMIT being exceeded, the device does the following: 1) Sets the VOUT_OV bit in STATUS_BYTE. 2) Sets the VOUT_OV and VOUT bits in STATUS_WORD. 3) Sets the VOUT_OV_FAULT bit in STATUS_VOUT. 4) Responds as specified in the MFR_FAULT_RESPONSE. Maxim Integrated 20 MAX34446 PMBus Power-Supply Data Logger VOUT_OV_WARN_LIMIT (42h) The VOUT_OV_WARN_LIMIT command sets the value of the output voltage that causes an output voltage high warning. The monitored voltage must drop by at least 2% below the limit before the warning is allowed to clear. This warning is masked until the output voltage is below this limit for the first time. The 2 data bytes are in DIRECT format. In response to the VOUT_OV_WARN_LIMIT being exceeded, the device does the following: 1) Sets the NONE OF THE ABOVE bit in STATUS_BYTE. 2) Sets the NONE OF THE ABOVE and VOUT bits in STATUS_WORD. 3) Sets the VOUT_OV_WARN bit in STATUS_VOUT. 4) Responds as specified in the MFR_FAULT_RESPONSE. VOUT_UV_WARN_LIMIT (43h) The VOUT_UV_WARN_LIMIT command sets the value of the output voltage that causes an output undervoltage warning. The monitored voltage must increase by at least 2% above the limit before the warning is allowed to clear. This warning is masked until the output voltage exceeds this limit for the first time. The 2 data bytes are in DIRECT format. In response to the VOUT_UV_WARN_LIMIT being exceeded, the device does the following: 1) Sets the NONE OF THE ABOVE bit in STATUS_BYTE. 2) Sets the NONE OF THE ABOVE and VOUT bits in STATUS_WORD. 3) Sets the VOUT_UV_WARN bit in STATUS_VOUT. 4) Responds as specified in the MFR_FAULT_RESPONSE. VOUT_UV_FAULT_LIMIT (44h) The VOUT_UV_FAULT_LIMIT command sets the value of the output voltage that causes an output undervoltage fault. The monitored voltage must increase by at least 2% above the limit before the fault is allowed to clear. This fault is masked until the output voltage exceeds this limit for the first time. The 2 data bytes are in DIRECT format. In response to violation of the VOUT_UV_FAULT_LIMIT, the device does the following: 1) Sets the NONE OF THE ABOVE bit in STATUS_BYTE. 2) Sets the NONE OF THE ABOVE and VOUT bits in STATUS_WORD. 3) Sets the VOUT_UV_FAULT bit in STATUS_VOUT. 4) Responds as specified in the MFR_FAULT_RESPONSE. IOUT_OC_WARN_LIMIT (46h) The IOUT_OC_WARN_LIMIT command sets the value of the current that causes an overcurrent warning. The monitored current must drop by at least 5% below the limit before the warning is allowed to clear. This warning is masked until the current is below this limit for the first time. The 2 data bytes are in DIRECT format. In response to violation of the IOUT_OC_WARN_LIMIT, the device does the following: 1) Sets the NONE OF THE ABOVE bit in STATUS_BYTE. 2) Sets the NONE OF THE ABOVE and MFR bits in STATUS_WORD. 3) Sets the OC_WARN bit in STATUS_MFR_SPECIFIC. 4) Responds as specified in the MFR_FAULT_RESPONSE. Maxim Integrated 21 MAX34446 PMBus Power-Supply Data Logger IOUT_OC_FAULT_LIMIT (4Ah) The IOUT_OC_FAULT_LIMIT command sets the value of the current that causes an overcurrent fault. The monitored current must drop by at least 5% below the limit before the fault is allowed to clear. This fault is masked until the current is below this limit for the first time. The 2 data bytes are in DIRECT format. In response to violation of the IOUT_OC_FAULT_LIMIT, the device does the following: 1) Sets the IOUT_OC bit in STATUS_BYTE. 2) Sets the IOUT_OC and MFR bits in STATUS_WORD. 3) Sets the OC_FAULT bit in STATUS_MFR_SPECIFIC. 4) Responds as specified in the MFR_FAULT_RESPONSE. The factory default value for IOUT_OC_FAULT_LIMIT is 0000h. This value disables the device from measuring current and instead selects voltage monitoring on this channel (if the channel is enabled with the MFR_MODE command). Any nonzero positive value written to IOUT_OC_FAULT_LIMIT causes the device to enable current measurement instead of voltage measurement. See Table 8. Table 8. IOUT_OC_FAULT_LIMIT IOUT_OC_FAULT_LIMIT VALUE 8000h to FFFFh DEVICE RESPONSE (ON THE ASSOCIATED PAGE) Negative values are invalid. 0000h Current measurement disabled (voltage measurement enabled). 0001h to 7FFFh Current measurement enabled (voltage measurement disabled). OT_FAULT_LIMIT (4Fh) The OT_FAULT_LIMIT command sets the temperature, in degrees Celsius, of the selected temperature sensor at which an overtemperature fault is detected. The monitored temperature must drop by at least 4NC below the limit before the fault is allowed to clear. This fault is masked until the temperature is below this limit for the first time. The 2 data bytes are in DIRECT format. In response to the OT_FAULT_LIMIT being exceeded, the device does the following: 1) Sets the TEMPERATURE bit in STATUS_BYTE. 2) Sets the TEMPERATURE and MFR bits in STATUS_WORD. 3) Sets the OT_FAULT bit in STATUS_MFR_SPECIFIC register. 4) Responds as specified in the MFR_FAULT_RESPONSE. The factory default value for OT_FAULT_LIMIT is 0000h. This value disables the device from measuring temperature on the selected temperature sensor. Any nonzero positive value written to OT_FAULT_LIMIT causes the device to enable temperature measurement. Table 9. OT_FAULT_LIMIT OT_FAULT_LIMIT VALUE 8000h to FFFFh Maxim Integrated DEVICE RESPONSE (ON THE ASSOCIATED PAGE) Negative values are invalid. 0000h Temperature measurement disabled. 0001h to 7FFFh Temperature measurement enabled. 22 MAX34446 PMBus Power-Supply Data Logger 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. This warning is masked until the temperature is below this limit for the first time. 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_BYTE. 2) Sets the TEMPERATURE and MFR bits in STATUS_WORD. 3) Sets the OT_WARN bit in STATUS_MFR_SPECIFIC register. 4) Responds as specified in the MFR_FAULT_RESPONSE. POWER_GOOD_ON (5Eh) The POWER_GOOD_ON command sets the value of the monitored voltage that causes the PG[3:0] outputs to assert. The monitored voltage must be above the associated POWER_GOOD_ON threshold before the associated PGn output is asserted and the POWER_GOOD# bit in the associated STATUS_MFR_SPECIFIC is cleared (Figure 3). The assertion of the PGn outputs can be delayed with the MFR_PG_DELAY command. All individual voltage channels must exceed POWER_GOOD_ON before the POWER_GOOD# bit in the STATUS_WORD is cleared. The POWER_GOOD_ON level is normally set higher than the POWER_GOOD_OFF level. The 2 data bytes are in DIRECT format. This command is ignored if the channel is disabled or configured to monitor current. POWER_GOOD_OFF (5Fh) The POWER_GOOD_OFF command sets the value of the monitored voltage that causes the PG[3:0] outputs to deassert after it has been asserted. A monitored voltage that falls below the associated POWER_GOOD_OFF threshold causes the associated PGn output to be deasserted and the POWER_GOOD# bit in STATUS_WORD and the POWER_GOOD# bit in the associated STATUS_MFR_SPECIFIC is set (Figure 3). The POWER_GOOD_OFF level is normally set lower than the POWER_GOOD_ON level. The 2 data bytes are in DIRECT format. This command is ignored if the channel is disabled or configured to monitor current. USER NOTE: The PGn outputs are forced high impedance if the channel is disabled or if the channel is configured to measure current. POWER_GOOD_ON POWER_GOOD_OFF MFR_PG_DELAY ADC INPUT PGn OUTPUT POWER_GOOD# BIT IN STATUS_MFR_SPECIFIC SYNC OUTPUT MFR_SYNC_CONFIG = 1428h 100kHz 200kHz 100kHz Figure 3. Power Good, SYNC Output, and Status Bit Timing Maxim Integrated 23 MAX34446 PMBus Power-Supply Data Logger STATUS_BYTE (78h) The STATUS_BYTE command returns 1 byte of information with a summary of the most critical faults. A value of 1 indicates that a fault or warning event has occurred and a 0 indicates otherwise. Bits for unsupported features are reported as 0. The STATUS_BYTE cannot be restored by RESTORE_DEFAULT_ALL command. Table 10 describes the STATUS_BYTE message content. This command is read-only. Table 10. STATUS_BYTE BIT 7:6 5 4 3 2 1 0 BIT NAME 0 VOUT_OV IOUT_OC 0 TEMPERATURE CML NONE OF THE ABOVE MEANING These bits always return a 0. An overvoltage fault has occurred. An overcurrent fault has occurred. This bit always returns a 0. A temperature fault or warning has occurred. A communication, memory, or logic fault has occurred. A fault or warning not listed in bits [7:1] has occurred. STATUS_WORD (79h) The STATUS_WORD command returns 2 bytes of information with a summary of the reason for a fault. The low byte of the STATUS_WORD is the same data as the STATUS_BYTE. Table 11 describes the STATUS_WORD message content. Table 11. STATUS_WORD BIT 15 14:13 12 BIT NAME VOUT 0 MFR 11 POWER_GOOD# 10:6 5 4 3 2 1 0 0 VOUT_OV IOUT_OC 0 TEMPERATURE CML NONE OF THE ABOVE MEANING An output voltage fault has occurred. These bits always return a 0. A bit in STATUS_MFR_SPECIFIC has been set. Global power good has been negated. Applies to all monitored voltages. This is a status-only bit and is not latched. These bits always return a 0. An overvoltage fault has occurred. An overcurrent fault has occurred. This bit always returns a 0. A temperature fault or warning has occurred. A communication, memory, or logic fault has occurred. A fault or warning not listed in bits [7:1] has occurred. STATUS_VOUT (7Ah) The STATUS_VOUT command returns 1 byte of information with contents as described in Table 12. Table 12. STATUS_VOUT BIT 7 6 5 4 3:0 BIT NAME VOUT_OV_FAULT VOUT_OV_WARN VOUT_UV_WARN VOUT_UV_FAULT 0 Maxim Integrated MEANING VOUT overvoltage fault. VOUT overvoltage warning. VOUT undervoltage warning. VOUT undervoltage fault. These bits always return a 0. 24 MAX34446 PMBus Power-Supply Data Logger STATUS_CML (7Eh) The STATUS_CML command returns 1 byte of information with contents as described in Table 13. Table 13. STATUS_CML BIT BIT NAME 7 COMM_FAULT An invalid or unsupported command has been received. 6 DATA_FAULT An invalid or unsupported data has been received. 5:1 0 0 FAULT_LOG_FULL MEANING These bits always return a 0. MFR_NV_FAULT_LOG is full and needs to be cleared. Note: When NV Fault Log Overwrite is enabled (NV_LOG_OVERWRITE = 1 in MFR_MODE), FAULT_LOG_FULL is set when the fault log is full, but clears when the fault log is overwritten since two fault logs are cleared before each overwrite. STATUS_MFR_SPECIFIC (80h) The STATUS_MFR_SPECIFIC command returns 1 byte of information with a summary of the reason for a fault. The STATUS_MFR_SPECIFIC message content is described in Table 14. Table 14. STATUS_MFR_SPECIFIC BIT BIT NAME 7 LOCKED MEANING Set when the device is password protected. This is a status-only bit and is not latched. 6 OT_WARN Overtemperature warning. 5 OT_FAULT Overtemperature fault. 4 WATCHDOG 3 0 2 POWER_GOOD# 1 OC_FAULT IOUT overcurrent fault. 0 OC_WARN IOUT overcurrent warning. A watchdog reset has occurred. This bit always returns a 0. Individual power good has been negated. Only applies to the selected page. This is a statusonly bit and is not latched. READ_VOUT (8Bh) The READ_VOUT command returns the actual measured remote voltage. The 2 data bytes are in DIRECT format. When the ENABLE pin is low, this command returns 0000h when read. READ_IOUT (8Ch) The READ_IOUT command returns the latest measured current value. The 2 data bytes are in DIRECT format. When the ENABLE pin is low, this command returns 0000h when read. READ_TEMPERATURE_1 (8Dh) The READ_TEMPERATURE_1 command returns the temperature reading. The 2 data bytes are in DIRECT format. When the ENABLE pin is low, this command returns 0000h when read. Maxim Integrated 25 MAX34446 PMBus Power-Supply Data Logger READ_POUT (96h) The READ_POUT command returns the latest calculated power-measurement value for ADC0/1 and ADC2/3 voltage/ current-coupled measurements as shown in Table 15. The 2 data bytes are in DIRECT format. When the ENABLE pin is low, this command returns 0000h when read. Table 15. READ_POUT Power-Measurement Values PAGE COMMAND 0 READ_VOUT 1 READ_IOUT 2 READ_VOUT 3 READ_IOUT DESCRIPTION READ_POUT = READ_VOUT x READ_IOUT READ_POUT = READ_VOUT x READ_IOUT PMBUS_REVISION (98h) The PMBUS_REVISION command returns the revision of the PMBus specification to which the device is compliant. The command has 1 data byte. Bits [7:4] indicate the revision of PMBus specification Part I to which the device is compliant. Bits [3:0] indicate the revision of PMBus specification Part II to which the device is compliant. This command is read-only. The PMBUS_REVISION value returned is always 11h, which indicates that the device is compliant with Part I Rev 1.1 and Part II Rev 1.1. MFR_ID (99h) The MFR_ID command returns the text (ISO/IEC 8859-1) character of the manufacturer’s (Maxim) identification. The default MFR_ID value is 4Dh (M). This command is read-only. MFR_MODEL (9Ah) The MFR_MODEL command returns the text (ISO/IEC 8859-1) character of the MAX34446 model number. The default MFR_MODEL value is 54h (T). This command is read-only. MFR_REVISION (9Bh) The MFR_REVISION command returns two text (ISO/IEC 8859-1) characters that contain the device revision numbers for hardware (upper byte) and firmware (lower byte). This command is read-only. MFR_LOCATION (9Ch) The MFR_LOCATION command loads the device with text (ISO/IEC 8859-1) characters that identify the facility that manufactures the power supply. The maximum number of characters is 8. This data is written to internal flash using the STORE_DEFAULT_ALL command. The factory default text string value is 10101010. MFR_DATE (9Dh) The MFR_DATE command loads the device with text (ISO/IEC 8859-1) characters that identify the date of manufacture of the power supply. The maximum number of characters is 8. This data is written to internal flash using the STORE_DEFAULT_ALL command. The factory default text string value is 10101010. MFR_SERIAL (9Eh) The MFR_SERIAL command loads the device with text (ISO/IEC 8859-1) characters that uniquely identify the device. The maximum number of characters is 8. This data is written to internal flash using the STORE_DEFAULT_ALL command. The factory default text string value is 10101010. The upper 4 bytes of MFR_SERIAL are used to unlock a device that has been password protected. The lower 4 bytes of MFR_SERIAL are not used to unlock a device and they can be set to any value. Maxim Integrated 26 MAX34446 PMBus Power-Supply Data Logger MFR_MODE (D1h) The MFR_MODE command is used to configure the device to support manufacturer-specific commands. Table 16 describes the MFR_MODE command. Table 16. MFR_MODE BIT BIT NAME MEANING 15 Setting this bit to 1 forces the device to log data into the nonvolatile fault log. Once set, the device clears this bit when the action is completed. The host must set again for subsequent FORCE_NV_FAULT_LOG action. If an error occurs during this action, the device sets the CML bit in STATUS_BYTE and STATUS_WORD; no bits are set in STATUS_CML. 14 Setting this bit to 1 forces the device to clear the nonvolatile fault log by writing FFh to all byte locations. Once set, the device clears this bit when the action is completed. The host must set CLEAR_NV_FAULT_LOG again for subsequent action. If an error occurs during this action, the device sets the CML bit in STATUS_BYTE and STATUS_WORD; no bits are set in STATUS_CML. While clearing the fault log, monitoring is stopped and commands should not be sent to the PMBus port. These bits determine if the device should log every ADC result or skip some readings to extend the time depth of the data buffer. 13:12 LOGSKIP[1:0] LOGSKIP1 LOGSKIP0 ADC RESULT LOGGING NV LOG DEPTH (ms) 0 0 Log every result 40 0 1 Log every 2nd result 80 1 0 Log every 4th result 160 1 1 Log every 8th result 320 11 SOFT_RESET This bit must be set, then cleared and set again within 8ms for a soft reset to occur. 10 LOCK This bit must be set, then cleared and set again within 8ms for the device to become password protected. This bit is cleared when the password is unlocked. 9 NV_LOG_OVERWRITE 8 0 This bit always returns a 0. 7 PG_PP_OD Applies to all PGn outputs. 0 = PGn push-pull output. 1 = PGn open-drain output. 6:2 0 These bits always return a 0. 0 = Do not overwrite the NV Fault Log. 1 = Overwrite the NV Fault Log once it is full. Note: The device clears two fault logs at a time when overwrite is enabled. These bits determine which channels of ADC0 to ADC3 are enabled. Unused channels should be connected to VSS. Whether voltage or current is monitored on the channel is selected with the IOUT_OC_FAULT_LIMIT command. 1:0 CHANNEL[1:0] Maxim Integrated CHANNEL1 CHANNEL0 NO. OF CHANNELS MONITORED ADC CHANNELS ENABLED 0 0 0 None 0 1 1 ADC0 1 0 2 ADC0 and ADC1 1 1 4 ADC0 to ADC3 27 MAX34446 PMBus Power-Supply Data Logger MFR_VOUT_PEAK (D4h) The MFR_VOUT_PEAK command returns the maximum measured output voltage. To reset this value to 0, write to this command with a data value of 0. The 2 data bytes are in DIRECT format. When the ENABLE pin goes low or the channel is disabled, this command resets to 0000h. MFR_IOUT_PEAK (D5h) The MFR_IOUT_PEAK command returns the maximum measured current. To reset this value to 0, write to this command with a data value of 0. The 2 data bytes are in DIRECT format. When the ENABLE pin goes low or the channel is disabled, this command resets to 0000h. MFR_TEMPERATURE_PEAK (D6h) The MFR_TEMPERATURE_PEAK command returns the maximum measured temperature. To reset this value to its lowest value, write to this command with a data value of 8000h. The 2 data bytes are in DIRECT format. When the ENABLE pin goes low or the channel is disabled, this command resets to 8000h. MFR_VOUT_MIN (D7h) The MFR_VOUT_MIN command returns the minimum measured output voltage. To reset this value, write to this command with a data value of 7FFFh. The 2 data bytes are in DIRECT format. When the ENABLE pin gos low or the channel is disabled, this command resets to 7FFFh. Maxim Integrated 28 MAX34446 PMBus Power-Supply Data Logger MFR_FAULT_RESPONSE (D9h) The MFR_FAULT_RESPONSE command specifies the response to each fault condition supported by the device. In response to a fault, the device always reports the fault in the appropriate status register. A CML fault cannot cause any device action other than setting the status bit. Table 17 describes the MFR_FAULT_RESPONSE command. Table 17. MFR_FAULT_RESPONSE BIT BIT NAME 7:6 NV_LOG_EN[1:0] 5 NV_LOG_OV 4 UV_OV_OC_FILTER 3 0 2 LATCHOFF 1:0 FAULT_EN[1:0] MEANING 0x = Never log MFR_NV_FAULT_LOG 10 = Log MFR_NV_FAULT_LOG on faults only. 11 = Log MFR_NV_FAULT_LOG on faults or warnings. This bit is only valid for pages 0 to 3. Other pages always return a 0. These bits are used only if the channel is configured to monitor voltage. 0 = Bits 7:6 are ignored for overvoltage faults or warnings. 1 = Bits 7:6 also applies to overvoltage faults or warnings. This bit is only valid for pages 0 to 3. Other pages always return a 0. 0 = Fault/warn on first sample excursion occurrence. 1 = Requires two consecutive sample excursions before a fault/warning is declared and action is taken. One passing sample is needed to clear a fault/warning. This bit always returns a 0. Normally after a fault, the device continues monitoring the afflicted parameter for the fault to clear and releases the FAULTn pin from being asserted low and logs future faults (if so enabled) once the currently accused fault clears. If this bit is set, the associated FAULTn output is latched in the asserted state (low) and no future fault logs are created until a VDD power cycle or hardware or software reset occurs. Warnings do not latch a channel off. 0 = Latchoff disabled. 1 = Latchoff enabled. 0x = Never assert the FAULTn pin. 10 = Assert the FAULTn pin on faults only. 11 = Assert the FAULTn pin on faults or warnings. Note: For fault responses, a fault is defined as either an undervoltage fault, overcurrent fault, or an overtemperature fault. Bit 6 allows the addition of an overvoltage fault to the fault condition. MFR_FAULT_RETRY (DAh) The MFR_FAULT_RETRY command sets the time the FAULTn output should remain active after the fault has been cleared. This command sets the time delay in multiples of 1ms. The 2 data bytes are in DIRECT format. When MFR_FAULT_RETRY = 0000h, the delay is disabled and the FAULTn output deasserts immediately after the fault condition is removed. MFR_PG_DELAY (DBh) The MFR_PG_DELAY command sets the delay time between when power good is determined and the associated PGn pin is asserted. This command sets the time delay in multiples of 1ms. The 2 data bytes are in DIRECT format. When MFR_PG_DELAY = 0000h, the delay is disabled and the PGn output is asserted immediately after power good is declared. Maxim Integrated 29 MAX34446 PMBus Power-Supply Data Logger MFR_NV_FAULT_LOG (DCh) Each time the MFR_NV_FAULT_LOG command is executed, the device returns a block of 255 bytes containing one of the 64 nonvolatile fault logs. The MFR_NV_FAULT_LOG command must be executed 64 times to dump the complete nonvolatile fault log. If the returned fault log contains all FFh, this indicates that the fault log has not been written by the device. As the device is operating, it is reading the latest operating conditions for voltage, current, and temperature and it is updating the status registers. All of this information is stored in on-board RAM. When a fault/warning is detected (if so enabled in MFR_FAULT_RESPONSE), the device automatically logs this information to one of the 64 nonvolatile fault logs. After 64 fault logs are written, bit 0 of STATUS_CML is set and the device can be configured (with the NV_LOG_ OVERWRITE bit in MFR_MODE) to either stop writing additional fault logs or to write over the oldest data. The host can clear the fault log by setting the CLEAR_NV_FAULT_LOG bit in MFR_MODE. All the latest status, temperature, and peak/minimum excursion information is logged. Also, 160 bytes of the 255-byte log are dedicated to report the latest ADC readings of voltage and current. The number of readings per ADC channels depends on the number of channels enabled. See Table 18. Also, the LOGSKIP bits in the MFR_MODE command can be used to allow the device to only log every 2nd, 4th, or 8th reading so that the fault log can record data over a longer time frame (see Table 16). Table 18. MFR_NV_FAULT_LOG 160-Byte Running Voltage/Current Log Format 1 CHANNEL ENABLED 80 Readings for ADC0, Data Buffer 0 to 79 2 CHANNELS ENABLED 4 CHANNELS ENABLED 40 Readings for ADC0, Data Buffer 0 to 39 20 Readings for ADC1, Data Buffer 20 to 39 20 Readings for ADC0, Data Buffer 0 to 19 20 Readings for ADC2, Data Buffer 40 to 59 40 Readings for ADC1, Data Buffer 40 to 79 20 Readings for ADC3, Data Buffer 60 to 79 Note: The number of ADC channels is configured with the CHANNEL bits in the MFR_MODE command. RAM STATUS_BYTE STATUS_WORD STATUS_VOUT STATUS_CML STATUS_MFR_SPECIFIC EACH FAULT IS WRITTEN INTO THE NEXT FAULT LOG FLASH FAULT LOG INDEX 0 (255 BYTES) MFR_VOUT_PEAK FAULT LOG INDEX 1 (255 BYTES) MFR_IOUT_PEAK MFR_TEMPERATURE_PEAK MFR_NV_FAULT_LOG MFR_VOUT_MIN MFR_TIME_COUNT MFR_POUT_PEAK MFR_POUT_AVG EACH COMMAND READ ACCESSES THE NEXT FAULT LOG FAULT OR WARNING OCCURRENCE FAULT LOG INDEX 2 (255 BYTES) MFR_IOUT_AVG MFR_TEMPERATURE_AVG READ_TEMPERATURE_1 FAULT LOG INDEX 63 (255 BYTES) READ_VOUT OR READ_IOUT (LATEST 20, 40, OR 80 READINGS) NOTE: AFTER DEVICE POWER-UP OR RESET, AT LEAST ONE NONFAULTY READING MUST OCCUR BEFORE A NEW FAULT LOG OCCURS. Figure 4. NV Fault Logging Arrangement Maxim Integrated 30 MAX34446 PMBus Power-Supply Data Logger If the device is not enabled to measure either current or voltage, or if a temperature sensor is disabled, the associated fault-log byte position returns 0000h. 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_MODE is toggled. Table 19 describes the 255 bytes returned by the MFR_NV_FAULT_LOG command. USER NOTE: VDD must be above 2.9V for the device to clear or log data into MFR_NV_FAULT_LOG. During a write to the fault log, the device temporarily stops monitoring and does not respond to SMBus commands. Table 19. MFR_NV_FAULT_LOG BYTE PARAMETER BYTE PARAMETER 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 00h/FAULT_LOG_INDEX FAULT_LOG_COUNT MFR_TIME_COUNT (LSW) MFR_TIME_COUNT (MSW) STATUS_BYTE / STATUS_CML STATUS_WORD STATUS_VOUT Pages 0/1 STATUS_VOUT Pages 1/2 STATUS_MFR_SPECIFIC Pages 0/1 STATUS_MFR_SPECIFIC Pages 2/3 STATUS_MFR_SPECIFIC Pages 4/5 STATUS_MFR_SPECIFIC Page 6/00h RESERVED (0000h) RESERVED (0000h) RESERVED (0000h) CURRENT_CHANNELS/00h (Note 1) READ_VOUT or IOUT Page 0 READ_VOUT or IOUT Page 1 READ_VOUT or IOUT Page 2 READ_VOUT or IOUT Page 3 MFR_VOUT or IOUT PEAK Page 0 MFR_VOUT or IOUT PEAK Page 1 MFR_VOUT or IOUT PEAK Page 2 MFR_VOUT or IOUT PEAK Page 3 MFR_VOUT_MIN or IOUTAVG Page 0 MFR_VOUT_MIN or IOUTAVG Page 1 MFR_VOUT_MIN or IOUTAVG Page 2 MFR_VOUT_MIN or IOUTAVG Page 3 RESERVED (0000h) 128 130 132 134 136 138 140 142 144 146 148 150 152 154 156 158 160 162 164 166 168 170 172 174 176 178 180 182 184 DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 58 60 62 64 BUFFER INDEX/NUMBER_OF_CH (Notes 2, 3) DATA BUFFER 0 DATA BUFFER 1 DATA BUFFER 2 186 188 190 192 DATA DATA DATA DATA BUFFER BUFFER BUFFER BUFFER 63 64 65 66 Maxim Integrated 31 MAX34446 PMBus Power-Supply Data Logger Table 19. MFR_NV_FAULT_LOG (continued) BYTE PARAMETER BYTE PARAMETER 66 DATA BUFFER 3 194 DATA BUFFER 67 68 70 DATA BUFFER 4 DATA BUFFER 5 196 198 DATA BUFFER 68 DATA BUFFER 69 72 74 DATA BUFFER 6 DATA BUFFER 7 200 202 DATA BUFFER 70 DATA BUFFER 71 76 78 DATA BUFFER 8 DATA BUFFER 9 204 206 DATA BUFFER 72 DATA BUFFER 73 80 82 84 86 88 90 92 94 96 98 100 102 104 106 108 110 112 114 116 118 120 122 124 126 DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA 208 210 212 214 216 218 220 222 224 226 228 230 232 234 236 238 240 242 244 246 248 250 252 254 DATA BUFFER 74 DATA BUFFER 75 DATA BUFFER 76 DATA BUFFER 77 DATA BUFFER 78 DATA BUFFER 79 RESERVED (0000h) READ_POUT Pages 0/1 READ_POUT Pages 2/3 MFR_POUT_PEAK Pages 0/1 MFR_POUT_PEAK Pages 2/3 MFR_POUT_AVG Pages 0/1 MFR_POUT_AVG Pages 2/3 RESERVED (0000h) READ_TEMPERATURE_1 Page 4 READ_TEMPERATURE_1 Page 5 READ_TEMPERATURE_1 Page 6 MFR_TEMPERATURE_PEAK Page 4 MFR_TEMPERATURE_PEAK Page 5 MFR_TEMPERATURE_PEAK Page 6 MFR_TEMPERATURE_AVG Page 4 MFR_TEMPERATURE_AVG Page 5 MFR_TEMPERATURE_AVG Page 6 LOG_VALID (Note 4) BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER BUFFER 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 Note 1: CURRENT_CHANNELS is a bitmask indicating which channels are enabled for current measurement. A reading of 0Ah indicates channels 1 and 3 are enabled to measure current. Note 2: BUFFER_INDEX is the index of the buffer where the most recent data is being written. The maximum value for BUFFER_INDEX is dependent upon the number of channels enabled. Note 3: NUMBER_OF_CH indicates how many of the voltage/current channels are enabled. Note 4: LOG_VALID is set to DDh if the fault log contains valid data. Maxim Integrated 32 MAX34446 PMBus Power-Supply Data Logger MFR_TIME_COUNT (DDh) The MFR_TIME_COUNT command returns the number of seconds of device lifetime operation. Once every hour, the device automatically stores this counter in flash memory. Also, the falling edge of the ENABLE input causes the device to attempt to store MFR_TIME_COUNT into flash memory as long as VDD is above 2.9V. The counter is a 32-bit value that rolls over. The latest stored value is automatically recalled from flash memory upon device power cycle, RST action, or a soft reset. This count can be reset to zero by writing a sequence of all zeros (00000000h), followed by all ones (FFFFFFFFh), followed by all zeros (00000000h) within 8ms. MFR_POUT_PEAK (E0h) The MFR_POUT_PEAK command returns the maximum calculated power. To reset this value to zero, write to this command with a data value of zero. The 2 data bytes are in DIRECT format. When the ENABLE pin goes low or the channel is disabled, this command resets to 0000h. MFR_POUT_AVG (E1h) The MFR_POUT_AVG command returns the calculated average power. To reset the average, write to this command with a data value of zero. Any other values written by this command are ignored. The 2 data bytes are in DIRECT format. When the ENABLE pin goes low or the channel is disabled, this command resets to 0000h. MFR_IOUT_AVG (E2h) The MFR_IOUT_AVG command returns the calculated average current. To reset the average, write to this command with a data value of zero. Any other values written by this command are ignored. The 2 data bytes are in DIRECT format. When the ENABLE pin goes low or the channel is disabled, this command resets to 0000h. MFR_TEMPERATURE_AVG (E3h) The MFR_TEMPERATURE_AVG command returns the calculated average temperature. To reset the average, write to this command with a data value of zero. Any other values written by this command are ignored. The 2 data bytes are in DIRECT format. When the ENABLE pin goes low or the channel is disabled, this command resets to 0000h. MFR_SYNC_CONFIG (EFh) The MFR_SYNC_CONFIG command determines the action of the SYNC output. The SYNC output can be programmed with the MFR_SYNC_CONFIG command to switch between two frequencies depending on the power-good state. MFR_SYNC_CONFIG is a 2-byte command. The MSB contains the SYNC frequency when all voltage channels have reached a power-good state. The LSB contains the SYNC frequency when any of the voltage channels is not in a powergood state. The format for the LSB and MSB to set the SYNC frequency is an integer between 8 and 200 (inclusive). The programmed integer is divided into the 4MHz on-board system oscillator to create the SYNC frequency. As shown in Table 20, if MFR_SYNC_CONFIG was programmed as 19C8h, then the SYNC output would be 160kHz in a power-good state and 20kHz when any of the voltage channels are not in a power-good state. If either byte of MFR_SYNC_CONFIG is set to 00h, the SYNC output is forced to high impedance during the respective power-good state. It is acceptable to have both the MSB and the LSB programmed to the same frequency, which eliminates the frequency dependency on the state of power good. See Figure 3 for more timing details. Table 20. MFR_SYNC_CONFIG Examples DIVIDE INTEGER (DECIMAL) SYNC FREQUENCY (SYSTEM OSCILLATOR/INTEGER) (kHz) 4 8 500 4 25 160 7Dh 4 125 32 C8h 4 200 20 MFR_SYNC_CONFIG MSB OR LSB VALUE (HEX) SYSTEM OSCILLATOR (MHz) 08h 19h Maxim Integrated 33 MAX34446 PMBus Power-Supply Data Logger Ordering Information Applications Information Power-Supply Decoupling To achieve the best results when using the device, decouple the VDD power supply with a 0.1µF capacitor. Use a high-quality, ceramic, surface-mount capacitor if possible. Surface-mount components minimize lead inductance, which improves performance, and ceramic capacitors tend to have adequate high-frequency response for decoupling applications. Decouple the REG25 and REG18 regulator outputs using 1µF and 10nF capacitors (one each per output). Open-Drain Pins SCL, SDA, FAULTn, and PGn (when set in MFR_MODE) are open-drain pins and require external pullup resistors connected to VDD to realize high-logic levels. Maxim Integrated PART TEMP RANGE PIN-PACKAGE MAX34446ETL+ -40NC to +105NC 40 TQFN-EP* MAX34446ETL+T -40NC to +105NC 40 TQFN-EP* +Denotes a lead(Pb)-free/RoHS-compliant package. T = Tape and reel. *EP = Exposed pad. Package Information For the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. PACKAGE TYPE PACKAGE CODE 40 TQFN-EP T4066+2 OUTLINE LAND PATTERN NO. NO. 21-0141 90-0053 34 MAX34446 PMBus Power-Supply Data Logger Typical Application Circuit/Block Diagram PG0 4MHz OSCILLATOR 5V POWERGOOD OUTPUTS PG2 PG3 MAX34446 OPTIONAL KEEP-ALIVE CIRCUIT (SEE NOTE) PG1 SYNC VDD FAULT0 POWER CONTROL FAULT1 FAULT2 REG25 FAULT OUTPUTS 2.5V VREG VSS REG18 16-BIT MAXQ RISC CORE 1.8V VREG FAULT3 FAULT4 FAULT5 FAULT6 4 CHANNELS OF MONITORED VOLTAGE OR CURRENT VOLTAGE RS+0 VSS RS-0 RS+1 PU RS-1 ADC LOG ENABLE RS-2 RS+3 PU RS-3 RST SDA TEMP SENSOR SCL ACCESS FOR CONFIGURATION AND LOG DATA A0 SMBus SLAVE INTERFACE CURRENT RS+2 MUX RS+4 RS-4 A1 MAX9938 CURRENT SENSE AMPLIFIER 2 CHANNELS OF MONITORED REMOTE TEMPERATURE THERMAL DIODE RS+5 FLASH RAM RS-5 THERMAL DIODE NOTE: THE OPTIONAL KEEP-ALIVE CIRCUIT IS USED TO PROVIDE AN ORDERLY SYSTEM SHUTDOWN AND TO ALLOW THE DEVICE TO STORE ANY FAULTS THAT ARE OCCURRING INTO FLASH MEMORY. Maxim Integrated 35 MAX34446 PMBus Power-Supply Data Logger Revision History REVISION NUMBER REVISION DATE 0 5/11 Initial release 1 1/12 Added the continuous power dissipation numbers and changed the lead temperature from +260°C to +300°C in the Absolute Maximum Ratings section; changed the VIL(MIN) and VI2C_IL(MIN) specs from -0.3V to 0V in the Recommended Operating Conditions table; changed the INL(MAX) spec from ±4 LSB to ±8LSB and removed the DNL parameter in the DC Electrical Characteristics table 2, 3 2 9/12 Added an NV fault log overwrite function and NV overwrite feature to the DC Electrical Characteristics table, Table 16, and MFR_NV_FAULT_LOG (DCh) section; updated the default value for 9Bh in Table 1 and MFR_REVISION (9Bh) section 3, 8, 25, 27, 30 DESCRIPTION PAGES CHANGED — Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits) shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance. Maxim Integrated 160 Rio Robles, San Jose, CA 95134 USA 1-408-601-1000 © 2012 Maxim Integrated Products, Inc. 36 Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.