Datasheet LTC3890-2 (Analog Devices) - 6

LTC3890-2
TYPICAL PERFORMANCE CHARACTERISTICS Efficiency and Power Loss vs Output Current Efficiency vs Output Current Efficiency vs Input Voltage
100 10000 100 100 VIN = 12V BURST EFFICIENCY V 90 V OUT = 8.5V OUT = 3.3V 90 98 V 80 1000 OUT = 3.3V 80 96 VOUT2 = 8.5V POWER LOSS (mW) 70 FCM LOSS 70 94 60 100 60 92 50 BURST LOSS 50 90 PULSE-SKIPPING 40 10 40 88 VOUT1 = 3.3V EFFICIENCY (%) LOSS EFFICIENCY (%) EFFICIENCY (%) 30 30 86 20 FCM EFFICIENCY 1 20 84 Burst Mode OPERATION 10 PULSE-SKIPPING 10 82 EFFICIENCY V I 0 0.1 IN = 12V LOAD = 2A 0 80 0.0001 0.001 0.01 0.1 1 10 0.0001 0.001 0.01 0.1 1 10 0 5 10 15 20 25 30 35 40 45 50 55 60 OUTPUT CURRENT (A) OUTPUT CURRENT (A) INPUT VOLTAGE (V) FIGURE 13 CIRCUIT 38902 G01 38902 G02 FIGURE 13 CIRCUIT 38902 G03 FIGURE 13 CIRCUIT
Load Step Load Step Load Step Burst Mode Operation Pulse-Skipping Mode Forced Continuous Mode
VOUT VOUT VOUT 100mV/DIV 100mV/DIV 100mV/DIV AC- AC- AC- COUPLED COUPLED COUPLED IL IL IL 2A/DIV 2A/DIV 2A/DIV 50µs/DIV 38902 G04 50µs/DIV 38902 G05 50µs/DIV 38902 G06 VIN = 12V VIN = 12V VIN = 12V 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 CONTINUOUS MODE VOUT2 2V/DIV VOUT2 2V/DIV Burst Mode OPERATION 1A/DIV VOUT1 VOUT1 2V/DIV 2V/DIV PULSE-SKIPPING MODE 5µs/DIV 38902 G07 2ms/DIV 38902 G08 2ms/DIV 38902 G09 VIN = 12V FIGURE 13 CIRCUIT FIGURE 13 CIRCUIT VOUT = 3.3V ILOAD = 200µA Rev. A 6 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 Applications Information Typical Applications Package Description Revision History Typical Application Related Parts