Datasheet LTC3887, LTC3887-1, LTC3887-2 (Analog Devices) - 9

link to page 4 LTC3887/LTC3887-1/ LTC3887-2
ELECTRICAL CHARACTERISTICS The
l
denotes the specifications which apply over the specified operating junction temperature range, otherwise specifications are at TA = 25°C. (Note 2) VIN = 12V, VRUN0,1 = 3.3V, fSYNC = 500kHz (externally driven) unless otherwise specified. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Leakage Current GPIO0, GPIO1
IGL Input Leakage Current 0V ≤ VPIN < 3.6V l ±5 µA
Digital Filtering of GPIO0, GPIO1
IFLTG Input Digital Filtering GPIO 3 µs
Digital Filtering of RUN0, RUN1
IFLTR Input Digital Filtering RUN 10 µs
PMBus Interface Timing Characteristics
fSMB Serial Bus Operating Frequency l 10 400 kHz tBUF Bus Free Time Between Stop and Start l 1.3 µs tHD,STA Hold time After Repeated Start Condition. l 0.6 µs After this Period, the First Clock is Generated tSU,STA Repeated Start Condition Setup Time l 0.6 µs tSU,STO Stop Condition Setup Time l 0.6 µs tHD,DAT Data Hold Time Receiving Data l 0 µs Transmitting Data l 0.3 0.9 µs tSU,DAT Data Setup Time Receiving Data l 0.1 µs tTIMEOUT_SMB Stuck PMBus Timer Non-Block Reads Measured from the Last PMBus Start Event 32 ms Stuck PMBus Timer Block Reads 150 ms tLOW Serial Clock Low Period l 1.3 10000 µs tHIGH Serial Clock High Period l 0.6 µs
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
Note 5:
The data format in PMBus is 5 bits exponent (signed) and 11 bits may cause permanent damage to the device. Exposure to any Absolute mantissa (signed). This limits the output resolution to 10 bits though the Maximum Rating condition for extended periods may affect device internal ADC is 16 bits and the calculations use 32-bit words. reliability and lifetime.
Note 6:
The data conversion is done in round robin fashion. All inputs
Note 2:
The LTC3887/LTC3887-1 are tested under pulsed load conditions signals are continuously converted for a typical latency of 90ms. Unless such that TJ ≈ TA. The LTC3887E/LTC3887E-1 are guaranteed to meet the MFR_ADC_CONTROL command is utilized. performance specifications from 0°C to 85°C. Specifications over the
Note 7:
The IOUT_CAL_GAIN = 1.0mΩ and MFR_IOUT_CAL_GAIN_TC = –40°C to 125°C operating junction temperature range are assured by 0.0. Value as read from READ_IOUT in amperes. design, characterization and correlation with statistical process controls.
Note 8:
Part tested with PWM disabled. Evaluation in application The LTC3887I/LTC3887I-1 are guaranteed over the full –40°C to 125°C demonstrates capability. TUE (%) = ADC Gain Error (%) + 100 • [Zero operating junction temperature range. TJ is calculated from the ambient Code Offset + ADC Linearity Error]/Actual Value. temperature TA and power dissipation PD according to the following formula:
Note 9:
All VOUT commands assume the ADC is used to auto-zero the output to achieve the stated accuracy. LTC3887 is tested in a feedback TJ = TA + (PD • θJA) loop that servos VOUT to a specified value. The maximum ambient temperature consistent with these specifications
Note 10:
The maximum V is determined by specific operating conditions in conjunction with board OUT voltage is 5.5V. layout, the rated package thermal impedance and other environmental
Note 11:
The maximum VIN voltage is 28V. factors.
Note 12:
When VIN < 6V, INTVCC must be tied to VIN.
Note 3:
All currents into device pins are positive; all currents out of device
Note 13:
EEPROM endurance and retention are guaranteed by design, pins are negative. All voltages are referenced to ground unless otherwise characterization and correlation with statistical process controls. The specified. minimum retention specification applies for devices whose EEPROM
Note 4:
Rise and fall times are measured using 10% and 90% levels. Delay has been cycled less than the minimum endurance specification. The times are measured using 50% levels. RESTORE_USER_ALL command (EEPROM read) is valid over the entire operating junction temperature range.
Note 14:
The LTC3887-2 quiescent current (IQ) equals the IQ of VIN plus the IQ of EXTVCC. Rev. F For more information www.analog.com 9 Document Outline Features Applications Typical Application Description Table of Contents Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Overview Main Control Loop EEPROM (NVM) Power Up and Initialization Soft-Start Sequencing EVENT-Based Sequencing Shutdown Light Load Current Operation Switching Frequency and Phase Output Voltage Sensing Current Sensing PolyPhase Load Sharing External/Internal Temperature Sense RCONFIG (Resistor Configuration) Pins Fault Detection and Handling Internal EEPROM with CRC Protection and ECC Serial Interface Communication Protection Device Addressing Responses to VOUT and IOUT Faults Output Overvoltage Fault Response Output Undervoltage Response Peak Output Overcurrent Fault Response Responses to Timing Faults Responses to VIN OV Faults Responses to OT/UT Faults Internal Overtemperature Fault/Warn Response External Overtemperature and Undertemperature Fault Response Responses to External Faults Fault Logging Bus Timeout Protection Similarity Between PMBus, SMBus and I2C 2-Wire Interface PMBus Serial Digital Interface PMBus Command Summary PMBus Commands *Data Format Applications Information Current Limit Programming ISENSE+ and ISENSE– Pins Low Value Resistor Current Sensing Inductor DCR Current Sensing Slope Compensation and Inductor Peak Current Inductor Value Calculation Inductor Core Selection Power MOSFET and Schottky Diode (Optional) Selection Variable Delay Time, Soft-Start and Output Voltage Ramping Digital Servo Mode Soft Off (Sequenced Off) INTVCC Regulator Topside MOSFET Driver Supply (CB, DB) (LTC3887, LTC3887-2) Undervoltage Lockout CIN and COUT Selection Fault Conditions Open-Drain Pins Phase-Locked Loop and Frequency Synchronization Minimum On-Time Considerations RCONFIG (External Resistor Configuration Pins) Voltage Selection Frequency and Phase Selection Using RCONFIG Address Selection Using RCONFIG Efficiency Considerations Checking Transient Response PC Board Layout Checklist PC Board Layout Debugging Design Example Additional Design Checks Connecting the USB to the I2C/SMBus/PMBus Controller to the LTC3887 In System LTpowerPlay: An Interactive GUI for Digital Power PMBus Communication and Command Processing PMBus Command Details Addressing and Write Protect General Configuration Registers On/Off/Margin PWM Config Voltage Input Voltage and Limits Output Voltage and Limits Current Input Current Calibration Output Current Calibration Input Current Output Current Temperature External Temperature Calibration External Temperature Limits Timing Timing—On Sequence/Ramp Timing—Off Sequence/Ramp Precondition for Restart Fault Response Fault Responses All Faults Fault Responses Input Voltage Fault Responses Output Voltage Fault Responses Output Current Fault Responses IC Temperature Fault Responses External Temperature Fault Sharing Fault Sharing Propagation Fault Sharing Response Scratchpad Identification Fault Warning and Status Telemetry NVM (EEPROM) Memory Commands Store/Restore Fault Logging Block Memory Write/Read Typical Applications Package Description Revision History Typical Application Related Parts