Datasheet LTC3851A (Analog Devices) - 6

LTC3851A
Typical perForMance characTerisTics Ratiometric Tracking with Master Input DC Supply Current Supply vs Input Voltage INTVCC Line Regulation
3.0 5.3 5.1 ILOAD = 0mA V 2.5 MASTER 4.9 ILOAD = 25mA 0.5V/DIV 2.0 4.7 V TAGE (V) 4.5 OUT 1.5 2A LOAD VOL 4.3 0.5V/DIV Y CURRENT (mA) V CC 1.0 4.1 INT SUPPL 3.9 10ms/DIV 3851A G11 0.5 3.7 0 3.5 4 8 12 16 20 24 28 32 36 40 4 8 12 16 20 24 28 32 36 40 INPUT VOLTAGE (V) INPUT VOLTAGE (V) 3851A G12 3851A G13
Maximum Current Sense Threshold Maximum Peak Current Sense Burst Mode Peak Current Sense vs Common Mode Voltage Threshold vs ITH Voltage Threshold vs ITH Voltage
90 90 60 DUTY CYCLE RANGE: 0% TO 100% 80 I 80 LIM = INTVCC MAXIMUIM 70 ILIM = INTVCC 50 70 60 60 40 I 50 LIM = FLOAT ILIM = FLOAT 50 (mV) 40 (mV) 30 40 30 THRESHOLD (mV) V SENSE I 20 LIM = GND V SENSE 30 ILIM = GND 20 10 V SENSE MINIMUIM 20 0 10 ILIM = FLOAT 10 –10 BURST COMPARATOR FALLING THESHOLD: V 0 –20 0 ITH = 0.4V 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 VSENSE COMMON MODE VOLTAGE (V) VITH (V) VITH (V) 3851A G14 3851A G15 3851A G16
Maximum Current Sense Maximum Current Sense Threshold vs Feedback Voltage TK/SS Pull-Up Current Threshold vs Duty Cycle (Current Foldback) vs Temperature
90 90 1.5 80 ILIM = INTVCC 80 ILIM = INTVCC 1.4 70 70 1.3 60 (mV) 60 1.2 ILIM = FLOAT ILIM = FLOAT 1.1 50 SENSE 50 1.0 40 40 ILIM = GND I 0.9 30 30 LIM = GND MAXIMUM V TK/SS CURRENT (µA) 0.8 20 20 0.7 CURRENT SENSE THRESHOLD (mV) 10 10 0.6 0 0 0.5 0 20 40 60 80 100 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 –75 –50 –25 0 25 50 75 100 125 150 DUTY CYCLE (%) FEEDBACK VOLTAGE (V) TEMPERATURE (°C) 3851A G17 3851A G18 3851A G19 3851afa 6 Document Outline Features Applications Description 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