Datasheet LTC7817 (Analog Devices) - 9

LTC7817
TYPICAL PERFORMANCE CHARACTERISTICS Maximum Current Sense Current Sense Threshold vs ITH Maximum Current Sense SENSE1,2– SENSE1,2 and SENSE3+ Current and SENSE3+ Current Threshold vs SENSE Common Maximum Current Sense Threshold Voltage Threshold vs ITH Voltage vs Voltage vs V Mode Voltage vs SENSE Common Mode Voltage
50 900 70 PULSE–SKIPPING 40 BURST MODE 800 SENSE1– CURRENT 60 FORCED CONTINUOUS 30 700 50 600 20 500 SENSE2– OR SENSE3+ CURRENT 40 10 400 30 0 300 20 –10 SENSE CURRENT (μA) 200 CURRENT SENSE THRESHOLD (mV) –20 100 10 MODE = INTVCC –30 0 MAXIMUM CURRENT SENSE THRESHOLD (mV) 0 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 0 5 10 15 20 25 30 35 40 0 5 10 15 20 25 30 35 40 ITH VOLTAGE (V) SENSE VOLTAGE (V) SENSE VOLTAGE (V) 7817 G19 7817 G20 7817 G21
SENSE1,2– and SENSE3+ Input SENSE1,2–, SENSE3+ Input SENSE1,2+ SENSE1,2 and SENSE3 + − and SENSE3 Input – Input Buck Foldback Current Limit Current vs Temperature Current vs T Current vs Temperature Current vs T
70 900 MODE = INTV 1.0 CC MODE = INTV 800 CC 0.8 60 SENSE = INTV 700 CC+0.5V 0.6 50 600 SENSE = 3.3V 0.4 SENSE = 12V 500 40 0.2 400 0.0 30 300 SENSE = 1V –0.2 20 200 –0.4 SENSE CURRENT (µA) SENSE CURRENT (μA) SENSE = 0V 100 SENSE1– = INTVCC–0.5V –0.6 10 0 –0.8 SENSE2–,SENSE3+ = INTV MAXIMUM CURRENT SENSE THRESHOLD (mV) CC–0.5V 0 –100 –1.0 0 100 200 300 400 500 600 700 800 –55 –25 5 35 65 95 125 155 –55 –25 5 35 65 95 125 155 FEEDBACK VOLTAGE (mV) TEMPERATURE (oC) TEMPERATURE (oC) 7817 G22 7817 G23 7817 G24
Oscillator Frequency Oscillator Frequency BOOST3 Charge Pump Output BOOST3 Charge Pump Output BOOST3 Charge Pump Output BOOST3 Charge Pump Output vs Temperature vs T Current vs Frequency Current vs Frequency Current vs SW3 Voltage Current vs SW3 V
10 100 100 R BOOST3 = 16V BOOST3–SW3 = 4V FREQ=374k (100kHz) 8 R 90 SW3 = 12V 90 FREQ = 0V FREQ=75k (500kHz) RFREQ=12.5k (3MHz) 80 80 6 FREQ=GND (380kHz) FREQ=INTVCC (2.25MHz) 70 70 4 60 60 2 50 50 0 40 40 30 30 –2 CHANGE IN FREQUENCY (%) CHARGE PUMP CURRENT (μA) 20 150°C CHARGE PUMP CURRENT (μA) 20 150°C –4 10 –55°C 10 –55°C 25°C 25°C –6 0 0 –55 –25 5 35 65 95 125 155 0 500 1000 1500 2000 2500 3000 0 5 10 15 20 25 30 35 TEMPERATURE (oC) FREQUENCY (kHz) SW3 VOLTAGE (V) 7817 G25 7817 G26 7817 G27 Rev 0 For more information www.analog.com 9 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Functional Diagram Operation Applications Information Typical Applications Typical Application Related Parts