Datasheet LTC7818 (Analog Devices) - 10

LTC7818
TYPICAL PERFORMANCE CHARACTERISTICS EXTV EXT CC V Switchover and INTVCC INTV INT CC V Undervoltage Lockout CC Undervoltage Lockout INTV CC Switchover and INTVCC INT CC V Voltage vs Current Voltage vs T V emperature oltage vs T Thresholds vs Temperature CC Voltage vs Current Thresholds vs T
5.4 5.4 4.4 VBIAS = 12V 5.2 5.2 4.3 INTV EXTV CC Voltage CC = 0V UVLO RISING 5.0 4.2 EXTVCC = 6V TAGE (V) 5.0 4.8 TAGE (V) VOL 4.1 EXTVCC = 5V V CC 4.8 VOL 4.6 EXTVCC Rising 4.0 V CC UVLO FALLING INT 4.6 OR EXT 4.4 UVLO THRESHOLD (V) 3.9 V CC EXTVCC Falling 4.2 INT 4.4 3.8 4.0 4.2 3.7 0 50 100 150 200 250 300 –55 –25 5 35 65 95 125 155 –55 –25 5 35 65 95 125 155 INTVCC LOAD CURRENT (mA) TEMPERATURE (oC) TEMPERATURE (oC) 7818 G28 7818 G29 7818 G30
RUN Pin Thresholds VBIAS V Quiescent Current BIAS Shutdown Current Shutdown Current vs Temperature vs T vs Temperature vs T vs VBIAS Input V vs Input V oltage oltage
1.26 40 8.0 Rising ALL CHANNELS ON 150°C 1.24 Falling 35 SLEEP MODE 7.0 25°C 1.22 VBIAS = 12V –55°C 30 6.0 1.20 1.18 μA) 25 5.0 EXTVCC = 0V, SENSE1–=0V 1.16 20 4.0 1.14 CURRENT ( 15 CURRENT (μA) 3.0 1.12 EXTVCC = 0V, SENSE1–=3.3V RUN THRESHOLD (V) V BIAS 10 V BIAS 2.0 1.10 1.08 5 1.0 EXTVCC = 12V, SENSE1–=3.3V 1.06 0 0 –55 –25 5 35 65 95 125 155 –55 –25 5 35 65 95 125 155 0 5 10 15 20 25 30 35 40 TEMPERATURE (oC) TEMPERATURE (oC) VBIAS INPUT VOLTAGE (V) 7818 G31 7818 G32 7818 G33
BOOST3 Charge Pump Output BOOST3 Charge Pump Output BOOST3 Charge Pump Output BOOST3 Charge Pump Output TRACK/SS Pull-Up Current TRACK/SS Pull–Up Current Current vs Frequency Current vs SW3 Voltage Current vs SW3 V vs Temperature
100 100 14.0 BOOST3 = 16V BOOST3–SW3 = 4V 90 SW3 = 12V 90 FREQ = 0V 80 13.5 μA) 80 μA) 70 70 µA) 13.0 60 60 50 50 12.5 40 40 30 30 12.0 TRACK/SS CURRENT ( CHARGE PUMP CURRENT ( 20 150°C CHARGE PUMP CURRENT ( 20 150°C 11.5 10 25°C 10 25°C –55°C –55°C 0 0 11.0 0 500 1000 1500 2000 2500 3000 0 5 10 15 20 25 30 35 –55 –25 5 35 65 95 125 155 FREQUENCY (kHz) SW3 VOLTAGE (V) TEMPERATURE (oC) 7818 G34 7818 G35 7818 G36 Rev. A 10 For more information www.analog.com 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 (VBIAS, EXTVCC, and INTVCC) Shutdown and Start-Up (RUN1, RUN2, RUN3 and TRACK/SS1, TRACK/SS2, SS3 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) Boost Controller Operation When VIN > VOUT Boost Controller at Low Input Voltage Buck Controller Output Overvoltage Protection Buck Foldback Current Channel 1 Power Good (PGOOD1) Boost Overvoltage Indicator (OV3) Applications Information Inductor Value Calculation Inductor Core Selection Current Sense Selection Low Value Resistor Current Sensing Inductor DCR Current Sensing Setting the Operating Frequency Selecting the Light-Load Operating Mode Power MOSFET Selection Boost CIN and COUT Selection Buck CIN and COUT Selection Setting the Buck Output Voltage Setting Boost Output Voltage (VPRG3 Pin) RUN Pins and Undervoltage Lockout Soft-Start and Tracking (TRACK/SS1, TRACK/SS2, SS3 Pins) Single Output Two-Phase Operation INTVCC Regulators Topside MOSFET Driver Supply (CB, DB) Minimum On-Time Considerations Boost Channel Current Monitor (IMON3) Fault Conditions: Buck Current Limit and Foldback Fault Conditions: Buck Overvoltage Protection (Crowbar) Fault Conditions: Overtemperature Protection Phase-Locked Loop and Frequency Synchronization Efficiency Considerations Checking Transient Response Buck Design Example PC Board Layout Checklist PC Board Layout Debugging Typical Applications Package Description Revision History Typical Application Related Parts