Datasheet LT3581 (Analog Devices) - 3

LT3581
ELECTRICAL CHARACTERISTICS The
l
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 5V, VSHDN = VIN, VFAULT = VIN, unless otherwise noted. (Note 2). PARAMETER CONDITIONS MIN TYP MAX UNITS
Minimum Input Voltage l 2.3 2.5 V VIN Overvoltage Lockout 22.1 23.5 25 V Positive Feedback Voltage l 1.195 1.215 1.230 V Negative Feedback Voltage l 3 9 16 mV Positive FB Pin Bias Current VFB = Positive Feedback Voltage, Current into Pin l 81 83.3 85 µA Negative FB Pin Bias Current VFB = Negative Feedback Voltage, Current out of Pin l 81 83.3 85.5 µA Error Amp Transconductance ΔI = 10μA 270 µmhos Error Amp Voltage Gain 70 V/V Quiescent Current Not Switching 1.9 2.3 mA Quiescent Current in Shutdown VSHDN = 0V 0 1 µA Reference Line Regulation 2.5V ≤ VIN ≤ 20V 0.01 0.05 %/V Switching Frequency, fOSC RT = 34k l 2.25 2.5 2.75 MHz RT = 432k l 180 200 220 kHz Switching Frequency in Foldback Compared to Normal fOSC 1/6 ratio Switching Frequency Range Free-Running or Synchronizing l 200 2500 kHz SYNC High Level for Synchronization l 1.3 V SYNC Low Level for Synchronization l 0.4 V SYNC Clock Pulse Duty Cycle VSYNC = 0V to 2V 20 80 % Recommended Minimum SYNC Ratio 3/4 fSYNC/fOSC Minimum Off-Time 45 ns Minimum On-Time 55 ns SW1 Current Limit At All Duty Cycles l 1.9 2.4 3 A Current Sharing (SW2/SW1) 78 % SW1 + SW2 Current Limit At All Duty Cycles, SW2/SW1 = 78% (Note 3) l 3.3 4.3 5.4 A Switch VCESAT SW1 & SW2 Tied Together, ISW1 + ISW2 = 2.75A 250 mV SW1 Leakage Current VSW1 = 5V 0.01 1 µA SW2 Leakage Current VSW2 = 5V 0.01 1 µA 3581fb For more information www.linear.com/LT3581 3 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram State Diagram Operation Applications Information Appendix Typical Applications Typical Application Related Parts