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.
MAX34446 PMBus Power-Supply Data Logger ABSOLUTE MAXIMUM RATINGS VDD to VSS............................................................-0.3V to +5.5V SDA or SCL to VSS................................................-0.3V to +5.5V RS-[5:0] to VSS......................................................-0.3V to +0.3V RS+[5:0] to VSS...... -0.3V to (VDD + 0.3V), not to exceed +5.5V RS+[5:0] to VSS with 100ω of series resistance...-0.3V to +2.0V All other pins relative to VSS..... -0.3V to (VDD + 0.
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 ADC Integral Nonlinearity ADC Offset RIN INL Remote Temperature Measurement Error (MAX3446 Error Only) 1.
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 4.7 Fs 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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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. After this command is sent, another command should not be sent for at least 250ms. 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.
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.
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.
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.
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.
MAX34446 PMBus Power-Supply Data Logger Table 19.
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.
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.
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.
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.
