LT3518 electrical characteristicsThe l denotes the specifications which apply over the full operatingtemperature range, otherwise specifications are at TA = 25°C. (Note 2) VIN = 5V, SHDN = 5V, PWM = 5V unless otherwise noted.PARAMETERCONDITIONSMINTYPMAXUNITS Minimum VIN Operating Voltage 3 V Maximum VIN Operating Voltage Continuous Operation (Note 3) 30 V Current Sense Voltage (VISP – VISN) VCTRL = 2V, VISP = 24V, VC = 1V l 96 100 103 mV VCTRL = 2V, VISP = 0V, VC = 1V 100 mV 10% Scale Current Sense Voltage (VISP – VISN) VCTRL = 100mV, VISP = 24V, VC = 1V 9 mV Current Sense Voltage Line Regulation 2V < VISP < 45V 0.03 %/V VIN Supply Current PWM > 1.5V, VC = 0V 6 10 mA PWM = 0V 4.5 mA SHDN = 0V 0.1 1 µA Switching Frequency RT = 16.7k l 0.85 1.0 1.15 MHz RT = 4.03k 2.25 2.5 2.7 MHz RT = 91.5k 220 250 270 kHz RT Voltage 1 V Soft-Start Pin Current SS = 0.5V, Out of Pin 6 9 12 µA SYNC Pull-Down Current (Into the Pin) VSYNC = 2V 60 µA SYNC Input Low 0.4 V SYNC Input High 1.5 V Maximum Duty Cycle RT = 91.5k (250kHz) 95 97 % SYNC = 300kHz Clock Signal, RT = 91.5k 94 96 % RT = 16.7k (1MHz) l 85 90 % RT = 4.03k (2.5MHz) 74 % Switch Current Limit 2.3 2.8 3.5 A Switch VCESAT ISW = 1.5A 400 mV Switch Leakage Current VSW = 45V, PWM = 0V 2 µA CTRL Input Bias Current Current Out of Pin, VCTRL = 0.1V 20 100 nA Error Amplifier Transconductance 550 µS VC Output Impedance 1000 kΩ VC Idle Input Bias Current PWM = 0, VC = 1V –20 0 20 nA FB Pin Input Bias Current Current Out of Pin, VFB = 0.5V 20 100 nA FB Pin Threshold l 0.98 1.01 1.04 V ISP , ISN Idle Input Bias Current PWM = 0V 300 nA ISP , ISN Full-Scale Input Bias Current ISP Tied to ISN, VISP = 24V, VCTRL = 2V 20 µA SHDN Voltage High l 1.2 V SHDN Voltage Low –40°C ≤ TJ ≤ 125°C 0.45 V 125°C < TJ ≤ 150°C 0.40 V SHDN Pin Bias Current 60 100 µA PWM Input High Voltage l 1.2 V PWM Input Low Voltage –40°C ≤ TJ ≤ 125°C 0.45 V 125°C < TJ ≤ 150°C 0.40 V PWM Pin Bias Current 60 120 µA 3518ff For more information www.linear.com/LT3518 3 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts