Datasheet LTC3878 (Analog Devices) - 5

LTC3878 Typical perForMance characTerisTics
Frequency vs Load Current Load Regulation FCM ITH Voltage vs Load Current
410 0 2.5 CONTINUOUS MODE VIN = 15V 370 2.3 –0.02 VOUT = 1.2V 330 FIGURE 7 CIRCUIT 2.1 DISCONTINUOUS MODE –0.04 290 1.9 250 –0.06 1.7 (%) 210 –0.08 1.5 VOLTAGE (V) 170 $V OUT 1.3 –0.10 I TH FREQUENCY (kHz) 130 1.1 VIN = 15V –0.12 VOUT = 1.2V 90 0.9 FIGURE 7 CIRCUIT VIN = 15V 50 V –0.14 OUT = 1.2V 0.7 CONTINUOUS MODE FIGURE 7 CIRCUIT DISCONTINUOUS MODE 10 –0.16 0.5 0 2 4 6 8 10 12 14 0 5 10 15 0 5 10 15 20 25 LOAD CURRENT (A) ILOAD (A) LOAD CURRENT (A) 3878 G12 3878 G10 3878 G11
Current Sense Voltage vs ITH Voltage On-Time vs ION Current Current Limit Foldback
300 10000 140 FIGURE 7 CIRCUIT VRNG = 1V 250 FIGURE 7 CIRCUIT 120 200 100 150 1000 100 80 50 60 ON-TIME (ns) 0 100 VRNG = 0.2V 40 –50 VRNG = 0.5V VRNG = 1.0V 20 CURRENT SENSE THRESHOLD (mV)–100 VRNG = 1.5V VRNG = 2.0V –150 10 MAXIMUM CURRENT SENSE THRESHOLD (mV) 0 0 0.5 1 1.5 2 2.5 1 10 100 0 0.2 0.4 0.6 0.8 I I TH VOLTAGE (V) ON CURRENT (µA) VFB (V) 3878 G14 3878 G13 3878 G15
Maximum VDS Current Sense Maximum VDS Current Sense Feedback Reference Voltage vs Threshold vs VRNG Voltage Threshold vs RUN/SS Voltage Temperature
300 140 0.808 0.806 250 120 0.804 100 TAGE (V) 200 0.802 80 150 0.800 60 0.798 100 40 0.796 50 20 FEEDBACK REFERENCE VOL 0.794 MAXIMUM CURRENT SENSE THRESOLD (mV) 0 MAXIMUM CURRENT SENSE THRESHOLD (mV) 0 0.792 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 1.5 2.0 2.5 3.0 –50 –30 –10 10 30 50 70 90 110 VRNG VOLTAGE (V) RUN/SS VOLTAGE (V) TEMPERATURE (°C) 3878 G16 3878 G17 3878 G18 3878fa Document Outline Features Description Applications Typical Application Absolute Maximum Ratings Pin Configuration order information Electrical Characteristics Typical Performance Characteristics Pin Functions Functional Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts