Datasheet LTC3772 (Analog Devices) - 5

LTC3772
W U TYPICAL PERFOR A CE CHARACTERISTICS Maximum Current Sense Foldback Frequency Threshold vs Temperature Soft-Start Time vs Temperature vs Temperature
300 1000 230 VFB = 0V IPRG = VIN 220 250 900 s) 210 µ 200 800 IPRG = FLOAT 200 150 700 190 IPRG = GND 180 100 600 FREQUENCY (Hz) SOFT-START TIME ( 170 50 500 160 MAXIMUM CURRENT SENSE THRESHOLD (mV) 0 400 150 –60 –40 –20 0 20 40 60 80 100 –60 –40 –20 0 20 40 60 80 100 –60 –40 –20 0 20 40 60 80 100 TEMPERATURE (°C) TEMPERATURE (°C) TEMPERATURE (°C) 3772 G13 3772 G14 3772 G15
Efficiency vs Load Current Efficiency vs Load Current
95 100 FIGURE 5 CIRCUIT VIN = 3.3V VOUT = 3.3V 90 VIN = 4.2V 90 85 VIN = 5V VOUT = 2.5V 80 80 VIN = 7V VOUT = 1.8V 75 70 EFFICIENCY (%) EFFICIENCY (%) 70 60 65 VOUT = 2.5V FIGURE 5 CIRCUIT 60 50 1 10 100 1000 10000 1 10 100 1000 10000 LOAD CURRENT (mA) LOAD CURRENT (mA) 3772 G16 3772 G17
Start-Up Load Step
V V OUT OUT 1V/DIV 100mV/DIV AC COUPLED ITH/RUN IL 1V/DIV 2A/DIV IL ILOAD 2A/DIV 2A/DIV 3772 G18 V 3772 G19 IN = 5V 500µs/DIV VIN = 5V 20µs/DIV VOUT = 2.5V VOUT = 2.5V FIGURE 5 CIRCUIT ILOAD = 100mA TO 1.5A FIGURE 5 CIRCUIT 3772f 5