Datasheet LTC3857-1 (Analog Devices) - 5

LTC3857-1
TYPICAL PERFORMANCE CHARACTERISTICS Efficiency and Power Loss vs Output Current Efficiency vs Output Current Efficiency vs Input Voltage
100 10000 100 98 VIN = 12V VOUT = 3.3V 90 VOUT = 3.3V 90 96 ILOAD = 5A FIGURE 13 CIRCUIT VIN = 5V 80 1000 80 94 POWER LOSS (mW) 70 70 VIN = 12V 92 60 100 60 90 50 50 88 40 10 40 EFFICIENCY (%) EFFICIENCY (%) EFFICIENCY (%) 30 86 30 20 1 20 84 10 10 VOUT = 3.3V 82 FIGURE 13 CIRCUIT 0 0.1 0 80 0.00001 0.0001 0.001 0.01 0.1 1 10 0.00001 0.0001 0.001 0.01 0.1 1 10 1 5 10 15 20 25 30 35 40 OUTPUT CURRENT (A) 38571 G01 OUTPUT CURRENT (A) INPUT VOLTAGE (V) BURST EFFICIENCY BURST LOSS 38571 G02 38571 G03 PULSE-SKIPPING PULSE-SKIPPING EFFICIENCY LOSS CCM EFFICIENCY CCM LOSS
Load Step Load Step Load Step (Burst Mode Operation) (Forced Continuous Mode) (Pulse-Skipping Mode)
VOUT VOUT VOUT 100mV/DIV 100mV/DIV 100mV/DIV INDUCTOR INDUCTOR CURRENT INDUCTOR CURRENT 2A/DIV CURRENT 2A/DIV 2A/DIV VIN = 12V 20μs/DIV 38571 G04 VIN = 12V 20μs/DIV 38571 G05 VIN = 12V 20μs/DIV 38571 G06 VOUT = 3.3V VOUT = 3.3V VOUT = 3.3V FIGURE 13 CIRCUIT FIGURE 13 CIRCUIT FIGURE 13 CIRCUIT
Inductor Current at Light Load Soft Start-Up Tracking Start-Up
FORCED V CONTINUOUS OUT2 2V/DIV MODE VOUT2 2V/DIV Burst Mode VOUT1 OPERATION 2V/DIV 1A/DIV VOUT1 2V/DIV PULSE- SKIPPING MODE 38571 G08 V 38571 G09 IN = 12V 5μs/DIV 38571 G07 20ms/DIV 20ms/DIV VOUT = 3.3V FIGURE 13 CIRCUIT FIGURE 13 CIRCUIT ILOAD = 200μA FIGURE 13 CIRCUIT 38571fc 5 Document Outline FEATURES DESCRIPTION APPLICATIONS TYPICAL APPLICATION ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION ORDER INFORMATION ELECTRICAL CHARACTERISTICS TYPICAL PERFORMANCE CHARACTERISTICS PIN FUNCTIONS FUNCTIONAL DIAGRAM OPERATION APPLICATIONS INFORMATION TYPICAL APPLICATIONS PACKAGE DESCRIPTION REVISION HISTORY TYPICAL APPLICATION RELATED PARTS