Datasheet LTC3772B (Analog Devices) - 5

LTC3772B
W U TYPICAL PERFOR A CE CHARACTERISTICS Maximum Current Sense Foldback Frequency Threshold vs Temperature Soft-Start Time vs Temperature vs Temperature
300 1100 230 VFB = 0V 220 250 1000 IPRG = VIN 210 µs) 200 900 200 150 IPRG = FLOAT 800 190 180 100 700 FREQUENCY (Hz) IPRG = GND SOFT-START TIME ( 170 50 600 160 MAXIMUM CURRENT SENSE THRESHOLD (mV) 0 500 150 –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) 3772B G13 3772B G14 3772B G15
Efficiency vs Load Current Efficiency vs Load Current
100 100 VIN = 3.3V VOUT = 3.3V 90 90 VIN = 4.2V VOUT = 2.5V 80 V 80 IN = 7V VOUT = 1.8V VIN = 5V 70 70 EFFICIENCY (%) 60 EFFICIENCY (%) 60 50 50 VOUT = 2.5V VIN = 5V FIGURE 5 CIRCUIT FIGURE 5 CIRCUIT 40 40 1 10 100 1000 10000 10 100 1000 10000 LOAD CURRENT (mA) LOAD CURRENT (mA) 3772B G16 3772B G17
Start-Up Load Step
V V OUT OUT 1V/DIV 100mV/DIV (AC) ITH/RUN IL 1V/DIV 2A/DIV INDUCTOR I CURRENT LOAD 2A/DIV 2A/DIV 3772B G18 3772B G19 V V 20µs/DIV IN = 5V 500µs/DIV IN = 5V V V OUT = 2.5V OUT = 2.5V R I LOAD = 1.5Ω LOAD = 100mA TO 1.5A FIGURE 5 CIRCUIT FIGURE 5 CIRCUIT 3772bfa 5