Datasheet LT8391 (Linear Technology) - 5

LT8391 ELECTRICAL CHARACTERISTICS
The
l
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. (Note 2). VIN = 12V, VEN/UVLO = 1.5V unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Current Comparator
Maximum Current Sense Threshold V(LSP-LSN) Buck, VFB = 0.8V l 35 50 65 mV Boost, VFB = 0.8V l 40 50 60 mV Reverse Current Sense Threshold V(LSP-LSN) Buck, VFB = 0.8V –4 mV Boost, VFB = 0.8V –4 mV LSP Pin Bias Current VLSP = VLSN = 12V 60 µA LSN Pin Bias Current VLSP = VLSN = 12V 60 µA
Fault
FB Overvoltage Threshold (VFB) Rising l 1.03 1.05 1.07 V FB Overvoltage Hysteresis l 15 25 35 mV FB Open LED Threshold (VFB) Rising, V(ISP-ISN) = 0V l 0.93 0.95 0.97 V FB Open LED Hysteresis V(ISP-ISN) = 0V l 35 50 65 mV FB Short LED Threshold (VFB) Falling l 0.24 0.25 0.26 V FB Short LED Hysteresis Hysteresis l 35 50 65 mV ISP/ISN Over Current Threshold V(ISP-ISN) VISP = 12V 750 mV ISP/ISN Open LED Threshold V(ISP-ISN) Falling, VFB = 1.0V l 8 10 12 mV ISP/ISN Open LED Hysteresis VFB = 1.0V l 3 5 7 mV FAULT Pull-Down Resistance 100 200 Ω SS Hard Pull-Down Resistance VEN/UVLO = 1.1V 100 200 Ω SS Pull-Up Current VFB = 0.8V, VSS = 0V 10.5 12.5 14.5 µA SS Pull-Down Current VFB = 1.0V, VSS = 2V 1.05 1.25 1.45 µA SS Fault Latch-Off Threshold Falling 1.7 V SS Fault Latch-Off Hysteresis 50 mV SS Fault Reset Threshold 0.2 V
Oscillator
RT Pin Voltage RT = 100kΩ 1.00 V Switching Frequency VSYNC/SPRD = 0V, RT = 226k l 190 200 210 kHz VSYNC/SPRD = 0V, RT = 100k l 380 400 420 kHz VSYNC/SPRD = 0V, RT = 59.0k l 570 600 630 kHz SYNC Frequency 150 650 kHz SYNC/SPRD Input Bias Current VSYNC/SPRD = 5V –0.1 0 0.1 µA SYNC/SPRD Threshold Voltage 0.4 1.5 V Highest Spread Spectrum Above Oscillator VSYNC/SPRD = 5V 12.5 14.5 16.5 % Frequency Lowest Spread Spectrum Below Oscillator VSYNC/SPRD = 5V –17.7 –15.7 –13.7 % Frequency 8391fa For more information www.linear.com/LT8391 5