Datasheet LTC7810 (Analog Devices) - 7

LTC7810
TYPICAL PERFORMANCE CHARACTERISTICS Efficiency and Power Loss vs Load Current Efficiency vs Load Current Efficiency vs Input Voltage
100 BURST EFFICIENCY 100 100 100 FIGURE 14 CIRCUIT 90 95 V PULSE–SKIPPING OUT = 12V 98 80 EFFICIENCY FCM EFFICIENCY 10 90 70 POWER LOSS (W) 85 96 60 FCM LOSS 1 80 ILOAD = 4A 50 PULSE– 75 94 SKIPPING 40 0.1 70 EFFICIENCY (%) LOSS EFFICIENCY (%) EFFICIENCY (%) 92 30 65 ILOAD = 100mA V 20 BURST LOSS IN = 24V VIN = 48V 0.01 60 VIN = 48V 90 VOUT = 12V 10 V FIGURE 14 CIRCUIT 55 IN = 100V FIGURE 14 CIRCUIT V V IN = 140V OUT = 12V 0 0.001 50 88 0.001 0.01 0.1 1 10 0.001 0.01 0.1 1 10 15 40 65 90 115 140 LOAD CURRENT (A) LOAD CURRENT (A) INPUT VOLTAGE (V) 7810 G01 7810 G02 7810 G03
Load Step Load Step Load Step Burst Mode Operation Pulse-Skipping Mode Forced Continuous Mode
V V V OUT OUT OUT 100mV/DIV 100mV/DIV 100mV/DIV INDUCTOR INDUCTOR INDUCTOR CURRENT CURRENT CURRENT 1A/DIV 1A/DIV 1A/DIV 200µs/DIV 7810 G04 200µs/DIV 7810 G05 200µs/DIV 7810 G06 VIN = 24V VIN = 24V VIN = 24V VOUT = 12V VOUT = 12V VOUT = 12V 100mA to 3A LOAD STEP 100mA to 3A LOAD STEP 100mA to 3A LOAD STEP FIGURE 14 CIRCUIT, PLLIN/SPREAD = GND FIGURE 14 CIRCUIT, PLLIN/SPREAD = GND FIGURE 14 CIRCUIT, PLLIN/SPREAD = GND
Regulated Feedback Voltage Inductor Current at Light Load Soft Start-Up vs Temperature
1.010 FORCED FIGURE 14 CIRCUIT CONTINUOUS RUN1,2 MODE 2V/DIV 1.005 TAGE (V) V BURST MODE OUT2 5V/DIV OPERATION 1A/DIV 1.000 PULSE VOUT1 SKIPPING 2V/DIV TED FEEDBACK VOL MODE 0.995 10µs/DIV 7810 G07 2ms/DIV 7810 G08 REGULA VIN = 24V VOUT = 12V 0.990 ILOAD = 100mA –55 –25 5 35 65 95 125 155 FIGURE 14 CIRCUIT, PLLIN/SPREAD = GND TEMPERATURE (°C) 7810 G09 Rev. A For more information www.analog.com 7 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