Datasheet LT3508 (Analog Devices) - 4

LT3508
TYPICAL PERFORMANCE CHARACTERISTICS Efficiency, VOUT = 5V Efficiency, VOUT = 3.3V Efficiency, VOUT = 1.8V
95 90 85 TA = 25°C TA = 25°C TA = 25°C f = 700kHz f = 700kHz f = 1MHz 90 V V IN = 12V 85 IN = 12V 80 VIN = 3.3V VIN = 24V VIN = 24V 85 80 75 VIN = 5V 80 VIN = 32V 75 V 70 V IN = 32V IN = 12V EFFICIENCY (%) 75 EFFICIENCY (%) 70 EFFICIENCY (%) 65 70 65 60 65 60 55 0 0.5 1 1.5 0 0.5 1 1.5 0 0.5 1 1.5 LOAD CURRENT (A) LOAD CURRENT (A) LOAD CURRENT (A) 3508 G01 3508 G02 3508 G03
Switch Current Limit Switch Current Limit Feedback Voltage vs Temperature vs Duty Cycle
0.810 3.0 3.0 TA = 25°C TYPICAL 2.5 2.5 0.805 2.0 2.0 MINIMUM TAGE (V) 0.800 1.5 1.5 CURRENT LIMIT (A) 1.0 CURRENT LIMIT (A) 1.0 FEEDBACK VOL 0.795 0.5 0.5 0.790 0 0 –50 –25 0 25 50 75 100 125 150 –50 –25 0 25 50 75 100 125 150 0 20 40 60 80 100 TEMPERATURE (°C) TEMPERATURE (°C) DUTY CYCLE (%) 3508 G04 3508 G05 3508 G06
Switching Frequency Switching Frequency vs RT vs Temperature Switching Frequency Foldback
175 1.2 3.0 TA = 25°C RT = 33.2k TA = 25°C 150 1.0 2.5 RT = 7.50k 125 0.8 2.0 100 (kΩ) 0.6 1.5 R T 75 0.4 1.0 RT = 33.2k 50 SWITCHING FREQUENCY (MHz) 0.2 SWITCHING FREQUENCY (MHz) 0.5 25 RT = 169k 0 0 0 0 0.5 1.0 1.5 2.0 2.5 –50 –25 0 25 50 75 100 125 150 0 100 200 300 400 500 600 700 800 FREQUENCY (MHz) TEMPERATURE (°C) FEEDBACK VOLTAGE (mV) 3508 G07 3508 G08 3508 G09 Rev. E 4 For more information www.analog.com Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Revision History Related Parts