Datasheet LTC7810 (Analog Devices) - 5

LTC7810
ELECTRICAL CHARACTERISTICS The
l
denotes the specifications which apply over the specified operating junction temperature range, otherwise specifications are at TA = 25°C, VIN = 12V, RUN1,2 = 5V, EXTVCC = 0V, DRVSET = INTVCC unless otherwise noted. (Note 2) SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Gate Drivers
TG or BG On-Resistance DRVSET OPEN Pull-up 2.0 Ω Pull-down 1.0 Ω TG or BG Transition Time DRVSET OPEN (Note 6) Rise Time CLOAD = 3300pF 40 ns Fall Time CLOAD = 3300pF 20 ns TG Off to BG On Delay DRVSET OPEN 35 ns Synchronous Switch-On Delay Time BG Off to TG On Delay DRVSET OPEN 35 ns Top Switch-On Delay Time tON(MIN) TG Minimum On-Time (Note 7) DRVSET OPEN 90 ns Maximum Duty Cycle Output in Dropout, V – SENSE < 8V 99 % Output in Dropout, V – SENSE ≥ 8V 100 % BOOST Charge Pump Available Output Current Output in Dropout, 105 µA VBOOST = 16V, VSW = 12V, FREQ = 0V BOOST-SW Charge Pump Voltage Output in Dropout, V – SENSE ≥ 8V 8.5 V
Low Dropout (LDO) Linear Regulators
DRVCC Regulation Point for EXTVCC and NDRV DRVSET = INTVCC 5.7 6.0 6.2 V LDOs DRVSET = 0V 7.6 8.0 8.3 V DRVSET OPEN 9.6 10.0 10.4 V DRVCC Regulation Point for Internal VIN LDO DRVSET = INTVCC 5.7 V DRVSET = 0V 7.6 V DRVSET OPEN 9.6 V VCCXO EXTVCC LDO Switchover Voltage EXTVCC Rising DRVSET = INTVCC 4.55 4.7 4.8 V DRVSET = 0V 7.3 7.5 7.8 V DRVSET OPEN 8.3 8.5 8.8 V EXTVCC Switchover Hysteresis 250 mV UVLO Undervoltage Lockout DRVCC Rising DRVSET = INTVCC l 3.9 4.1 4.3 V DRVSET = 0V l 5.3 5.5 5.7 V DRVSET OPEN l 7.2 7.5 7.8 V DRVCC Falling DRVSET = INTVCC l 3.8 4.0 4.1 V DRVSET = 0V l 5.0 5.2 5.4 V DRVSET OPEN l 6.4 6.7 7.0 V REGSD Threshold Voltage VREGSD Rising 1.2 V REGSD Charge Current VREGSD = 1V, REGSD Rising 10 μA REGSD Discharge Current VREGSD = 1V, REGSD Falling 10 μA INTVCC Regulation Point 4.5 V
Spread Spectrum Oscillator and Phase-Locked Loop
fOSC Low Fixed Frequency VFREQ = 0V, PLLIN/SPREAD = 0V 160 200 230 kHz High Fixed Frequency VFREQ = INTVCC, PLLIN/SPREAD = 0V 230 300 340 kHz Programmable Frequency RFREQ = 25kΩ, PLLIN/SPREAD = 0V 105 kHz RFREQ = 65kΩ, PLLIN/SPREAD = 0V 375 430 485 kHz RFREQ = 105kΩ, PLLIN/SPREAD = 0V 780 kHz Rev. A For more information www.analog.com 5 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Functional Diagram Operation Main Control Loop Power and Bias Supplies (VIN, NDRV, EXTVCC, DRVCC, REGSD) Boost Supply and Dropout (BOOST and SW pins) Start-Up and Shutdown (RUN, TRACK/SS, OVLO Pins) Light Load Operation: Burst Mode Operation, Pulse Skipping or Forced Continuous Mode (MODE Pin) Frequency Selection, Spread Spectrum, and Phase-Locked Loop (FREQ and PLLIN/SPREAD Pins) Applications Information Current Sense Selection Low Value Resistor Current Sensing Inductor DCR Sensing Setting the Operating Frequency Selecting the Light-Load Operating Mode Inductor Value Calculation Inductor Core Selection Power MOSFET Selection CIN and COUT Selection Setting the Output Voltage RUN Pins and Overvoltage/Undervoltage Lockout Tracking and Soft-Start (TRACK/SS1, TRACK/SS2 Pins) Single Output Two-Phase Operation DRVCC Regulators Topside MOSFET Driver Supply (CB, DB) Burst Clamp Programming Fault Conditions: Current Limit and Current Foldback Fault Conditions: Overvoltage Protection (Crowbar) Fault Conditions: Overtemperature Protection Phase-Locked Loop and Frequency Synchronization Minimum On-Time Considerations Efficiency Considerations Checking Transient Response Design Example PC Board Layout Checklist PC Board Layout Debugging Typical Applications Package Description Revision History Typical Application Related Parts