Datasheet LT3681 (Analog Devices) - 4

LT3681
W U TYPICAL PERFOR A CE CHARACTERISTICS TA = 25°C unless otherwise noted. Effi ciency (VOUT = 5.0V) Effi ciency (VOUT = 3.3V) Effi ciency vs Switching Frequency
100 100 90 90 90 V 85 V IN = 12V IN = 12V 80 80 VIN = 7V VIN = 24V 80 70 70 VIN = 24V V 75 60 60 IN = 12V 50 50 VIN = 24V 70 40 40 65 EFFICIENCY (%) EFFICIENCY (%) EFFICIENCY (%) 30 30 60 20 20 VOUT = 3.3V L: NEC PLC-0745-4R7 55 10 10 L: NEC PLC-0745-4R7 L = 10µH f: 800kHz f: 800kHz LOAD = 1A 0 0 50 0.0001 0.001 0.01 0.1 1 10 0.0001 0.001 0.01 0.1 1 10 0 0.5 1 1.5 2 2.5 3 LOAD CURRENT (A) LOAD CURRENT (A) SWITCHING FREQUENCY (MHz) 3681 G01 3681 G02 3681 G03
No Load Supply Current vs No Load Supply Current Temperature Maximum Load Current
90 100 4.0 VIN = 12V 80 VOUT = 3.3V 90 3.5 70 µA) µA) 60 80 INCREASED SUPPLY 3.0 CURRENT DUE TO CATCH 50 DIODE LEAKAGE AT 70 HIGH TEMPERATURE 2.5 40 30 60 2.0 LOAD CURRENT (A) SUPPLY CURRENT ( SUPPLY CURRENT ( 20 50 V 1.5 OUT = 3.3V L = 4.7µH 10 f = 800 kHz FRONT PAGE APPLICATION 40 0 1.0 5 10 20 25 30 35 –40 –20 0 20 40 60 80 0 15 5 10 15 20 25 30 TEMPERATURE ( INPUT VOLTAGE (V) °C) INPUT VOLTAGE (V) 3681 G05 3681 G04 3681 G06
Maximum Load Current Switch Current Limit Switch Current Limit
4.0 4.0 4.5 DUTY CYCLE = 10 % 4.0 3.5 3.5 3.0 3.0 3.0 2.5 DUTY CYCLE = 90 % 2.5 2.5 2.0 1.5 2.0 2.0 LOAD CURRENT (A) 1.0 SWITCH CURRENT LIMIT(A) SWITCH CURRENT LIMIT (A) VOUT = 5.0V 1.5 1.5 L = 4.7µH 0.5 f = 800 kHz 1.0 1.0 0 5 10 15 20 25 30 0 20 40 60 80 100 –50 –25 0 25 50 75 100 125 INPUT VOLTAGE (V) DUTY CYCLE (%) TEMPERATURE (°C) 3681 G08 3681 G07 3681 G09 3681f 4