Datasheet LT3991, LT3991-3.3, LT3991-5 (Analog Devices) - 6

LT3991/LT3991-3.3/LT3991-5
Typical perForMance characTerisTics TA = 25°C, unless otherwise noted. Minimum Switch On-Time/ LT3991-X Frequency Foldback Switch Off-Time Soft-Start
900 400 2.5 800 350 tOFF(MIN) 1A LOAD 2.0 700 300 600 250 1.5 500 tOFF(MIN) 0.5A LOAD 200 400 150 1.0 300 t 200 SWITCH ON/OFF TIME (ns) 100 ON(MIN) SWITCH CURRENT LIMIT (A) 0.5 SWITCHING FREQUENCY (kHz) 50 100 0 0 0 0 20 40 60 80 100 –55 –25 5 35 65 95 125 155 0 0.25 0.5 0.75 1 1.25 1.5 1.75 2 V TEMPERATURE (°C) SS PIN VOLTAGE (V) OUT (% OF REGULATION VOLTAGE) 3991 G17 3991 G18 3991 G30
Minimum Input Voltage Minimum Input Voltage EN Threshold
5.0 6.4 1.05 VOUT = 3.3V VOUT = 5V 4.8 1.04 6.2 4.6 1.03 4.4 6.0 1.02 TO START 4.2 TO START TAGE (V) 1.01 RISING THRESHOLD TAGE (V) TAGE (V) 5.8 4.0 1.00 3.8 5.6 0.99 TO RUN INPUT VOL 3.6 INPUT VOL FALLING THRESHOLD 5.4 0.98 THRESHOLD VOL 3.4 0.97 5.2 TO RUN 3.2 0.96 3.0 5.0 0.95 0 200 400 600 800 1000 1200 0 200 400 600 800 1000 1200 –55 –25 5 35 65 95 125 155 LOAD CURRENT (mA) LOAD CURRENT (mA) TEMPERATURE (°C) 3991 G19 3991 G20 3971 G21
Transient Load Response, Load Current Stepped from 25mA Boost Diode Forward Voltage Power Good Threshold (Burst Mode Operation) to 525mA
1.6 95 1.4 94 93 1.2 VOUT 92 100mV/DIV 1.0 TAGE (%) 91 0.8 90 0.6 89 BOOST DIODE VF (V) 88 0.4 THRESHOLD VOL 87 0.2 IL 86 500mA/DIV 0 85 0 250 500 750 1000 1250 1500 –55 –25 5 35 65 95 125 155 10µs/DIV 3991 G24 BOOST DIODE CURRENT (mA) TEMPERATURE (°C) VIN = 48V, VOUT = 3.3V 3991 G22 3991 G23 COUT = 47µF 3991fa 6 Document Outline Features Applications Description Typical Application 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