POWER LOSS (W) LTC7806 40V, Low I , 3MHz, 2-Phase Q Synchronous Boost Controller FEATURES DESCRIPTION n 2-Phase Operation Reduces Required Input and The LTC 7806 is a high performance 2-phase single out- Output Capacitance and Power Supply Induced Noise put synchronous boost converter controller that drives n Synchronous Operation for Highest Efficiency two N-channel power MOSFET stages out-of-phase. Its andReduced Heat Dissipation constant-frequency current mode architecture allows a n Wide Input Voltage Range: 4.5V to 40V, phase-lockable switching frequency of up to 3MHz. High OperatesDown to 1V After Start-Up frequency 2-phase operation reduces input and output n Output Voltage Up to 40V capacitor requirements and allows the use of smaller n Low Operating Quiescent Current: 18A inductors compared to the single-phase equivalent. n PassThru Operation: 100% Duty Cycle Capability Synchronous rectification increases efficiency, reduces for Synchronous MOSFET power losses, and eases thermal requirements, simpli- n R or Inductor DCR Current Sensing SENSE fying high power boost applications. The synchronous n Spread Spectrum Operation PassThru capability also minimizes losses in automotive n Programmable Fixed Frequency (100kHz to 3MHz) start-stop applications. n Phase-Lockable Frequency (100kHz to 3MHz) n The LTC7806 operates from a wide 4.5V to 40V input sup- Selectable Continuous, Pulse-Skipping, or Low Ripple Burst Mode Operation at Light Loads ply range. When biased from the boost converter output, n Input Current Monitor Output the LTC7806 can operate from an input supply as low as n Internal LDO Powers Gate Drive from V or EXTV 1V after start-up. The very low no-load quiescent current BIAS CC n Low Shutdown I : 1.5A extends operating run time in battery powered systems. Q n Side Wettable 28-Lead 4mm 5mm QFN Package OPTI-LOOP compensation allows the transient response n AEC-Q100 Automotive Qualification in Process to be optimized over a wide range of output capacitance and ESR values. The LTC7806 features a precision 1.2V APPLICATIONS reference, a power good output indicator, and an inductor n Automotive and Transportation current monitor. n Audio and RF Power Amplifiers All registered trademarks and trademarks are the property of their respective owners. Protected by U.S. patents, including 5481178, 5705919, 5929620, 6144194, 6177787, 6580258. n Industrial and Medical n Communications TYPICAL APPLICATION 2H 2m V Efficiency and Power Loss IN V IN 1.2V TO 40V 10F vs Output Current + RUN SENSE1 START-UP 2 100 100 ABOVE 5V SENSE1 BG1 95 BOOST1 EFFICIENCY 0.1F 10 LTC7806 90 SW1 TG1 BOOST1,2 85 V BIAS 1 INTV V CC FB POWER LOSS 80 2H 2m V V IN OUT 0.1 75 24V/12A + SENSE2 ITH 220F 70 SS SENSE2 0.01 BG2 FREQ 65 Burst Mode OPERATION BOOST2 OVMODE V FOLLOWS OUT V = 12V IN VPRG 0.1F 4.7F V FOR 60 0.001 IN PLLIN/SPREAD SW2 V > 24V 0.0001 0.001 0.01 0.1 1 10 IN MODE TG2 GND OUTPUT CURRENT (A) 7806 TA01b 7806 TA01a Rev. 0 1 Document Feedback For more information www.analog.com EFFICIENCY (%)LTC7806 TABLE OF CONTENTS Features ..................................................... 1 Applications Information ................................ 17 Applications ................................................ 1 Inductor Value Calculation ......................................17 Typical Application ........................................ 1 Inductor Core Selection ..........................................17 Description.................................................. 1 Current Sense Selection ..........................................17 Absolute Maximum Ratings .............................. 3 Low Value Resistor Current Sensing.......................18 Order Information .......................................... 3 Inductor DCR Current Sensing ...............................19 Pin Configuration .......................................... 3 Setting the Operating Frequency .............................20 Electrical Characteristics ................................. 4 Selecting the Light Load Operating Mode ...............21 Typical Performance Characteristics ................... 7 Power MOSFET Selection .......................................22 Pin Functions .............................................. 10 C and C Selection ...........................................22 IN OUT Block Diagram ............................................. 12 PolyPhase Operation ...............................................24 Operation................................................... 13 Setting the Output Voltage ......................................24 Main Control Loop ..................................................13 RUN Pin and Undervoltage Lockout .......................24 Power and Bias Supplies .......................................13 Soft-Start ...............................................................25 Shutdown and Start-Up (RUN, SS Pins) ................13 INTV Regulators ..................................................25 CC Light Load Operation: Burst Mode Operation, Topside MOSFET Driver Supply (C , D ) ................26 B B Pulse-Skipping or Forced Continuous Mode Minimum On-Time Considerations .........................26 (MODE Pin) .............................................................14 Current Monitor (IMON) .........................................27 Frequency Selection, Spread Spectrum and Fault Conditions: Overtemperature Protection ........27 Phase-Locked Loop Phase-Locked Loop and Frequency (FREQ and PLLIN/SPREAD Pins) ............................15 Synchronization ......................................................27 PolyPhase Applications (CLKOUT Pin) ...................15 Efficiency Considerations ........................................27 Overvoltage Mode Selection (OVMODE Pin) ...........15 Checking Transient Response .................................28 Operation When V > Regulated V ..................16 Design Example ......................................................29 IN OUT Operation at Low Input Voltage...............................16 PC Board Layout Checklist ......................................30 Power Good (PGOOD Pin) ......................................16 PC Board Layout Debugging ...................................32 Typical Applications ...................................... 33 Package Description ..................................... 37 Typical Application ....................................... 38 Related Parts .............................................. 38 Rev. 0 2 For more information www.analog.com