Datasheet LT1766, LT1766-5 (Analog Devices) - 6

LT1766/LT1766-5
TYPICAL PERFORMANCE CHARACTERISTICS Switch Peak Current Limit FB Pin Voltage and Current SHDN Pin Bias Current
2.5 1.234 2.0 250 TA = 25°C CURRENT REQUIRED TO FORCE SHUTDOWN 1.229 200 (FLOWS OUT OF PIN). AFTER SHUTDOWN, 1.5 CURRENT DROPS TO A FEW μA TYPICAL 2.0 CURRENT (μA) 1.224 150 TAGE (V) VOLTAGE 1.219 1.0 100 GUARANTEED MINIMUM CURRENT CURRENT (μA) 1.5 1.214 12 FEEDBACK VOL AT 2.38V STANDBY THRESHOLD 0.5 SWITCH PEAK CURRENT (A) (CURRENT FLOWS OUT OF PIN) 1.209 6 1.0 1.204 0 0 0 20 40 60 80 100 –50 –25 0 25 50 75 100 125 150 –50 –25 0 25 50 75 100 125 150 DUTY CYCLE (%) JUNCTION TEMPERATURE (°C) JUNCTION TEMPERATURE (°C) 1766 G01 1766 G02 1766 G03
Lockout and Shutdown Thresholds Shutdown Supply Current Shutdown Supply Current
2.4 40 300 VSHDN = 0V TA = 25°C LOCKOUT 35 TA = 25°C 2.0 250 30 VIN = 60V 1.6 200 25 VIN = 15V 1.2 20 150 15 0.8 100 SHDN PIN VOLTAGE (V) 10 START-UP INPUT SUPPLY CURRENT (μA) INPUT SUPPLY CURRENT (μA) 0.4 50 5 SHUTDOWN 0 0 0 –50 –25 0 25 50 75 100 125 150 0 10 20 30 40 50 60 0 0.1 0.2 0.3 0.4 0.5 JUNCTION TEMPERATURE (°C) INPUT VOLTAGE (V) SHUTDOWN VOLTAGE (V) 1766 G04 1766 G05 1766 G06
Error Amplifi er Transconductance Error Amplifi er Transconductance Frequency Foldback
2500 3000 200 600 TA = 25°C TA = 25°C PHASE 500 2000 2500 150 GAIN PHASE (DEG) 400 1500 2000 100 VC 300 R C SWITCHING OUT 1000 1500 GAIN (μMho) OUT 50 VFB 2 • ( 10–3) 200k 12pF FREQUENCY 200 OR FB CURRENT (μA) TRANSCONDUCTANCE (μmho) 500 1000 ERROR AMPLIFIER EQUIVALENT CIRCUIT 0 SWITICHING FREQUENCY (kHz) 100 FB PIN RLOAD = 50Ω CURRENT 500 0 –50 0 –50 –25 0 25 50 75 100 125 150 100 1k 10k 100k 1M 10M 0 0.5 1.0 1.5 JUNCTION TEMPERATURE (°C) FREQUENCY (Hz) VFB (V) 1766 G08 1766 G07 1766 G09 1766fc 6