Datasheet LT3972 (Analog Devices) - 5

LT3972
TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C unless otherwise noted. Switch Voltage Drop BOOST Pin Current Feedback Voltage
700 120 840 105 600 90 820 500 75 400 60 800 300 45 VOLTAGE DROP (mV) 200 FEEDBACK VOLTAGE (mV) 780 BOOST PIN CURRENT (mA) 30 100 15 0 0 760 0 1 2 3 4 5 0 1 2 3 4 5 –50 –25 0 25 50 75 100 125 150 SWITCH CURRENT (A) SWITCH CURRENT (A) TEMPERATURE (°C) 3972 G10 3972 G11 3972 G12
Switching Frequency Frequency Foldback Minimum Switch On-Time
1.20 1200 140 1.15 1000 120 1.10 100 800 1.05 80 1.00 600 60 0.95 FREQUENCY (MHz) 400 40 0.90 SWITCHING FREQUENCY (kHz) 200 MINIMUM SWITCH ON-TIME (ns) 20 0.85 0.80 0 0 –50 –25 0 25 50 75 100 125 150 0 100 200 300 400 500 600 700 800 900 –50 –25 0 25 50 75 100 125 150 TEMPERATURE (°C) FB PIN VOLTAGE (mV) TEMPERATURE (°C) 3972 G13 3972 G14 3972 G15
Soft-Start RUN/SS Pin Current Boost Diode
7 12 1.4 6 1.2 10 5 1.0 8 (V) F 4 0.8 6 3 0.6 4 BOOST DIODE V 2 0.4 SWITCH CURRENT LIMIT (A) RUN/SS PIN CURRENT (μA) 1 2 0.2 0 0 0 0 0.5 1 1.5 2 2.5 3 3.5 0 5 10 15 20 25 30 35 0 0.5 1.0 1.5 2.0 RUN/SS PIN VOLTAGE (V) RUN/SS PIN VOLTAGE (V) BOOST DIODE CURRENT (A) 3972 G16 3972 G17 3972 G18 3972fa 5