Datasheet LT1072 - 5

LT1072
W U TYPICAL PERFOR A CE CHARACTERISTICS Supply Current vs Supply Voltage Driver Current* vs Switch Current Supply Current vs Input Voltage* (Shutdown Mode)
80 15 160 TJ = 25°C TJ = 25°C 70 14 NOTE THAT THIS CURRENT DOES NOT 140 13 INCLUDE DRIVER CURRENT, WHICH IS 60 A FUNCTION OF LOAD CURRENT AND A) 120 12 DUTY CYCLE. µ 50 90% DUTY CYCLE 100 11 VC = 50mV 40 10 80 50% DUTY CYCLE 30 9 60 8 DRIVER CURRENT (mA) 20 SUPPLY CURRENT (mA) 10% DUTY CYCLE SUPPLY CURRENT ( 40 7 10 6 20 VC = 0V 0% DUTY CYCLE 0 5 0 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 0 10 20 30 40 50 60 0 10 20 30 40 50 60 SWITCH CURRENT (A) INPUT VOLTAGE (V) SUPPLY VOLTAGE (V) *AVERAGE LT1072 POWER SUPPLY CURRENT IS *UNDER VERY LOW OUTPUT CURRENT CONDITIONS, LT1072 • TPC12 FOUND BY MULTIPLYING DRIVER CURRENT BY DUTY CYCLE FOR MOST CIRCUITS WILL APPROACH DUTY CYCLE, THEN ADDING QUIESCENT CURRENT 10% OR LESS LT1072 • TPC10 LT1072 • TPC11
Normal/Flyback Mode Threshold on Feedback Pin Shutdown Mode Supply Current Error Amplifier Transconductance
500 –24 200 5000 (V 490 –22 180 4500 Gm = ∆I C PIN) FEEDBACK PIN CURRENT ( ∆V (FB PIN) 480 –20 160 4000 A) mho) 470 –18 µ 140 µ 3500 460 FEEDBACK PIN VOLTAGE –16 120 TJ = 150°C 3000 (AT THRESHOLD) 450 –14 100 2500 440 –12 80 2000 430 –10 µ 60 – 55 1500 A) °C ≤ TJ ≤ 125°C FEEDBACK PIN CURRENT SUPPLY CURRENT ( FEEDBACK PIN VOLTAGE (mV) 420 –8 1000 (AT THRESHOLD) 40 TRANSCONDUCTANCE ( 410 –6 20 500 400 –4 0 0 –50 –25 0 25 50 75 100 125 150 0 10 20 30 40 50 60 70 80 90 100 –75 –50 –25 0 25 50 75 100 125 150 TEMPERATURE (°C) V TEMPERATURE (C°) C PIN VOLTAGE (mV) LT1072 • TPC13 LT1072 • TPC14 LT1072 • TPC15
Idle Supply Current vs Shutdown Thresholds Temperature Feedback Pin Clamp Voltage
400 –400 11 500 VC = 0.6V 10 450 350 –350 CURRENT (OUT OF VC PIN) 9 400 V 300 –300 C –55°C PIN VOLTAGE ( 8 350 250 –250 7 VSUPPLY = 60V 300 25°C 200 –200 6 250 V VOLTAGE SUPPLY = 3V 150°C 150 –150 5 200 PIN VOLTAGE (mV) µA) CV 4 150 100 –100 FEEDBACK VOLTAGE (mV) V IDLE SUPPLY CURRENT (mA) 3 100 C VOLTAGE IS REDUCED UNTIL 50 REGULATOR CURRENT DROPS –50 2 50 BELOW 300µA 0 0 1 0 –75 –50 –25 0 25 50 75 100 125 150 –75 –50 –25 0 25 50 75 100 125 150 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 TEMPERATURE (°C) TEMPERATURE (°C) FEEDBACK CURRENT (mA) LT1072 • TPC16 LT1072 • TPC17 LT1072 • TPC18 1072fc 5