LT3746 elecTrical characTerisTicsThe l denotes the specifications which apply over the full operatingtemperature range, otherwise specifications are at TA = 25°C. VIN = 24V, VCC = 3.3V, VEN/UVLO = 1.5V, VFB = 1.5V,VISP = VISN = 0V, RT = 105k, RISET = 60.4k, CCAP = 0.47µF to VIN, unless otherwise noted. SYMBOLPARAMETERCONDITIONSMINTYPMAXUNITSGate Driver VBIAS CAP Bias Voltage (VIN – VCAP) 7V < VIN < 55V 6.54 6.77 7.00 V ICAP CAP Bias Current Limit (VIN – VCAP) = VBIAS – 0.5V 22 mA GATE High Level (VIN – VGATE) IGATE = –100mA 0.4 V GATE Low Level (VGATE – VCAP) IGATE = 100mA 0.3 V GATE Rise Time CGATE = 3.3nF to VIN, VIN = 12V 30 ns GATE Fall Time CGATE = 3.3nF to VIN, VIN = 12V 30 ns LED Driver VISET Trimmed ISET Pin Voltage l 1.181 1.205 1.229 V LEDxx Operating Voltage VISP = VISN = VLEDxx l 0 13 V LEDxx Leakage Current LED Channel Off, VISP = VISN = 5V, 0.2 µA VLEDxx = 3V ILED LED Constant Sink Current VISP = VISN = 5V, VLEDxx = 0.5V REGDC = 0x00 7 11.5 16 mA REGDC = 0x20 15.5 21.5 27.5 mA REGDC = 0x3F 23 30 37 mA ∆ILEDC Current Mismatch Between Channels VISP = VISN = 5V, VLEDxx = 0.5V, 8 20 % REGDC = 0x20 (Note 6) ∆ILEDD Current Mismatch Between Devices VISP = VISN = 5V, VLEDxx = 0.5V, –15 5 20 % REGDC = 0x20 (Note 7) ∆ILINE LED Current Line Regulation VISP = VISN = 5V, VLEDxx = 0.5V, –0.2 0.2 1 %/V REGDC = 0x20, VCC = 3V to 5.5V (Note 8) ∆ILOAD LED Current Load Regulation VISP = VISN = 5V, REGDC = 0x20, –1 1 3 %/V VLEDxx = 0.5V to 2.5V (Note 9) VOPEN Open LED Threshold VISP = VISN = 5V, VLEDxx Falling 0.1 V VSHT Short LED Threshold VISP = VISN = 5V, VLEDxx Rising 3.65 3.9 4.15 V TLEDON Minimum LED On Time VISP = VISN = 5V, REGGS = 0x001 0.5 µs PWMCK LOGIC VCC = 3V to 5.5V High Level Voltage 2.4 VCC V Low Level Voltage 0 0.6 V Thermal Protection ITSET TSET Output Current VTSET = 1V l 19.0 19.8 20.6 µA TSET Over Temperature Threshold TA = 25°C 510 mV Serial Data Interface Single-Ended Input (Note 10) VCC = 3V to 5.5V VSIH High Level Voltage 2.4 VCC V VSIL Low Level Voltage 0 0.6 V ISI Single-Ended Input Current VCC = 3V to 5.5V, SI = VCC or GND –0.2 0.2 µA Single-Ended Output (Note 10) VCC = 3V to 5.5V V VSOH High Level Voltage ISO = –1mA VCC – 0.1 V VSOL Low Level Voltage ISO = 1mA 0.1 V 3746fa 4 For more information www.linear.com/3746 Document Outline Description Typical Application Absolute Maximum Ratings Pin Configuration Electrical Characteristics Pin Functions Block Diagram Applications Information Typical Application Related Parts