Datasheet LTC7812 (Analog Devices) - 9

LTC7812
TYPICAL PERFORMANCE CHARACTERISTICS Maximum Current Sense Maximum Current Sense TRACK/SS1 and SS2 Pull-Up Current Threshold vs Duty Cycle Threshold vs ITH Voltage vs Temperature
80 60 6.00 DUTY CYCLE = 10% 70 50 5.75 TAGE (mV) 40 60 TAGE (mV) 5.50 30 50 BOOST 5.25 BUCK 20 40 5.00 10 30 4.75 0 20 –10 TRACK/SS CURRENT (µA) 4.50 PULSE-SKIPPING 10 –20 FORCED CONTINUOUS 4.25 MAXIMUM CURRENT SENSE VOL MAXIMUM CURRENT SENSE VOL Burst Mode OPERATION 0 –30 4.00 0 10 20 30 40 50 60 70 80 90 100 0 0.2 0.4 0.6 0.8 1 1.2 1.4 –75 –50 –25 0 25 50 75 100 125 150 DUTY CYCLE (%) ITH (V) TEMPERATURE (°C) 7812 G28 7812 G29 7812 G30
Shutdown Current Shutdown Current vs Temperature vs Input Voltage Quiescent Current vs Temperature
20 25 80 VBIAS = 12V 18 70 20 16 60 14 15 50 12 40 BOTH CHANNELS ON 10 10 30 CHANNEL 1 ON SHUTDOWN CURRENT (µA) 8 SHUTDOWN CURRENT (µA) 20 5 QUIESCENT CURRENT (µA) 6 10 4 0 0 –75 –50 –25 0 25 50 75 100 125 150 5 10 15 20 25 30 35 40 –75 –50 –25 0 25 50 75 100 125 150 TEMPERATURE (°C) VBIAS INPUT VOLTAGE (V) TEMPERATURE (°C) 7812 G31 7812 G32 7812 G33
Oscillator Frequency Buck Foldback Current Limit vs Temperature
70 600 65 60 550 FREQ = INTVCC TAGE (mV) 55 50 45 500 40 35 450 30 25 FREQUENCY (kHz) 400 20 15 FREQ = GND 10 350 MAXIMUM CURRENT SENSE VOL 5 0 300 0 100 200 300 400 500 600 700 800 –75 –50 –25 0 25 50 75 100 125 150 VFB1 FEEDBACK VOLTAGE (mV) TEMPERATURE (°C) 7812 G34 7812 G35 7812fc For more information www.linear.com/LTC7812 9 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 Typical Application Related Parts