Datasheet LTC3855 (Analog Devices) - 7

LTC3855 Typical perForMance characTerisTics
Tracking Up and Down Quiescent Current with External Ramp vs Temperature without EXTVCC INTVCC Line Regulation
4.5 5.5 TK/SS1 TK/SS2 4.0 5.0 2V/DIV VOUT1 3.5 4.5 3.0 V VOUT2 4.0 OUT1 2.5 TAGE (V) VOUT2 500mA/DIV 2.0 VOL 3.5 V CC 10ms/DIV 3855 G07 1.5 INT V 3.0 IN = 12V V QUIESCENT CURRENT (mA) 1.0 OUT1 = 1.8V, 1.5Ω LOAD VOUT2 = 1.2V, 1Ω LOAD 0.5 2.5 0 2.0 –50 –25 0 25 50 75 100 125 0 10 20 30 40 TEMPERATURE (°C) INPUT VOLTAGE (V) 3855 G08 3855 G09
Maximum Current Sense Current Sense Threshold Threshold vs Common Mode Maximum Current Sense vs ITH Voltage Voltage Threshold vs Duty Cycle
80 80 80 ILIM = INTVCC ILIM = INTVCC 60 70 70 ILIM = INTVCC 60 60 40 ILIM = FLOAT 50 50 (mV) ILIM = FLOAT ILIM = FLOAT 20 40 40 ILIM = GND V SENSE 30 30 0 ILIM = GND ILIM = GND 20 20 –20 CURRENT SENSE THRESHOLD (mV) 10 CURRENT SENSE THRESHOLD (mV) 10 –40 0 0 0 0.5 1 1.5 2 0 2 4 6 8 10 12 0 20 40 60 80 100 VITH (V) VSENSE COMMON MODE VOLTAGE (V) DUTY CYCLE (%) 3855 G10 3855 G11 3855 G12
Maximum Current Sense Voltage vs Feedback Voltage (Current TK/SS Pull-Up Current Foldback) vs Temperature
90 1.6 80 ILIM = INTVCC 70 60 ILIM = FLOAT 1.4 50 40 ILIM = GND 30 1.2 TK/SS CURRENT (µA) 20 10 MAXIMUM CURRENT SENSE THRESHOLD (mV) 0 1.0 0 0.1 0.2 0.3 0.4 0.5 0.6 –50 –25 0 25 50 75 100 125 FEEDBACK VOLTAGE (V) TEMPERATURE (°C) 3855 G14 3855 G13 3855f Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order information Electrical Characteristics Typical Performance Characteristics Pin Functions Functional Block Diagram Operation Applications Information Typical Applications Package Description Related Parts