Datasheet LTC3889 (Analog Devices) - 9

LTC3889
ELECTRICAL CHARACTERISTICS The
l
denotes the specifications which apply over the specified operating junction temperature range, otherwise specifications are at TJ = 25°C (Note 2). VIN = 16V, EXTVCC = 0V, VRUN0 = 1.8V, VRUN1 = 1.8V fSYNC = 250kHz (externally driven), and all programmable parameters at factory default unless otherwise specified. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
tSU(STA) Repeated Start Condition Setup Time l 0.6 10000 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 32/255 ms Stuck PMBus Timer Block Reads 255 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 8:
Part tested with PWM disabled. Evaluation in application may cause permanent damage to the device. Exposure to any Absolute demonstrates capability. TUE (%) = ADC Gain Error (%) + 100 • Maximum Rating condition for extended periods may affect device [Zero Code Offset + ADC Linearity Error]/Actual Value. reliability and lifetime.
Note 9:
All VOUT commands assume the ADC is used to auto-zero the
Note 2:
The LTC3889 is tested under pulsed load conditions such that TJ ≈ output to achieve the stated accuracy. LTC3889 is tested in a feedback TA. The LTC3889E is guaranteed to meet performance specifications from loop that servos VOUT to a specified value. 0°C to 85°C. Specifications over the –40°C to 125°C operating junction
Note 10:
The maximum programmable VOUT voltage is 40V. temperature range are assured by design, characterization and correlation
Note 11:
The maximum V with statistical process controls. The LTC3889I is guaranteed over the IN voltage is 60V. –40°C to 125°C operating junction temperature range. T
Note 12:
When VIN < 6V, DRVCC must be tied to VIN. J is calculated from the ambient temperature, T
Note 13:
EEPROM endurance is guaranteed by design, characterization A, and power dissipation, PD, according to the following formula: and correlation with statistical process controls. Data retention is T production tested via a high temperature bake at wafer level.The minimum J = TA + (PD • θJA) retention specification applies for devices whose EEPROM has been cycled The maximum ambient temperature consistent with these specifications less than the minimum endurance specification. The RESTORE_USER_ALL is determined by specific operating conditions in conjunction with board command (EEPROM read) is valid over the entire operating temperature layout, the rated package thermal impedance and other environmental range. factors.
Note 14:
The LTC3889 quiescent current (I
Note 3:
All currents into device pins are positive; all currents out of device Q) equals the IQ of VIN plus the I pins are negative. All voltages are referenced to ground unless otherwise Q of EXTVCC. specified.
Note 15:
The LTC3889 includes overtemperature protection that is intended to protect the device during momentary overload conditions.
Note 4:
Rise and fall times are measured using 10% and 90% levels. Delay Junction temperature will exceed 125°C when overtemperature protection times are measured using 50% levels. is active. Continuous operation above the specified maximum operating
Note 5:
The data format in PMBus is 5 bits exponent (signed) and 11 bits junction temperature may impair device reliability. mantissa (signed). This limits the output resolution to 10 bits though the
Note 16:
Write operations above T internal ADC is 16 bits and the calculations use 32-bit words. J = 85°C or below 0°C are possible although the Electrical Characteristics are not guaranteed and the EEPROM
Note 6:
The data conversion is done in round robin fashion. All input will be degraded. Read operations performed at temperatures between signals are continuously converted for a typical latency of 90ms unless the –40°C and 125°C will not degrade the EEPROM. Writing to the EEPROM MFR_ADC_CONTROL command is utilized. above 85°C will result in a degradation of retention characteristics.
Note 7:
The IOUT_CAL_GAIN = 1.0mΩ and MFR_IOUT_TC = 0.0. Value as
Note 17:
Limits guaranteed by TSNS voltage and current measurements read from READ_IOUT in amperes. during test, including ADC readback. Rev. 0 For more information www.analog.com 9 Document Outline Table of Contents Features Applications Typical Application Description Table of Contents Absolute Maximum Ratings Order Information Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Overview Main Control Loop EEPROM CRC Protection Power-Up and Initialization Soft-Start Time-Based Sequencing Event-Based Sequencing Shutdown Light-Load Current Operation PWM Loop Compensation Switching Frequency and Phase Output Voltage Sensing Output Current Sensing Input Current Sensing PolyPhase Load Sharing External/Internal Temperature Sense RCONFIG (Resistor Configuration) Pins Fault Handling Status Registers and ALERT Masking Mapping Faults to FAULT Pins Power Good Pins 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 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 Optional Schottky Diode Selection CIN and COUT Selection Variable Delay Time, Soft-Start and Output Voltage Ramping Digital Servo Mode Soft Off (Sequenced Off) DRVCC Regulator Topside MOSFET Driver Supply (CB, DB) Undervoltage Lockout Fault Indications Open-Drain Pins Phase-Locked Loop and Frequency Synchronization Minimum On-Time Considerations External Temperature Sense Derating EEPROM Retention at Temperature Input Current Sense Amplifier External Resistor Configuration Pins (RCONFIG) Voltage Selection Frequency Selection Phase Selection Address Selection Using RCONFIG Efficiency Considerations Programmable Loop Compensation Checking Transient Response PolyPhase Configuration PC Board Layout Checklist PC Board Layout Debugging Design Example Additional Design Checks Connecting the USB to I2C/SMBus/PMBus Adapter to the LTC3889 In System LTpowerPlay: An Interactive GUI for Digital Power PMBus Communication and Command Processing PMBus Command Details Addressing and Write Protect General Configuration COMMANDS On/Off/Margin PWM Configuration Voltage Input Voltage and Limits Output Voltage and Limits Output Current and Limits Input Current and Limits Temperature External Temperature Calibration 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 EEPROM Memory Commands Store/Restore Fault Logging Fault Log Operation Block Memory Write/Read Typical Applications Package Description Typical Application Related Parts