LTC3873-5 ELECTRICAL CHARACTERISTICSThe l denotes the specifi cations which apply over the full operatingtemperature range, otherwise specifi cations are at TA = 25°C. VCC = 5V unless otherwise noted. (Note 2)PARAMETERCONDITIONSMINTYPMAXUNITS Input DC Supply Current Typicals at VCC = 5V (Note 4) Normal Operation VITH = 1.9V 300 400 μA Shutdown VRUN/SS = 0V 50 80 μA UVLO VCC = UVLO Threshold – 100mV, VRUN/SS = VCC 35 50 μA Undervoltage Lockout Threshold VCC Rising l 3.8 4.1 4.4 V VCC Falling l 2.5 2.9 3.3 V VCC Hysteresis l 0.9 1.25 1.7 V Shutdown Threshold (at RUN/SS) VRUN/SS Falling l 0.5 0.7 0.9 V VRUN/SS Rising 0.6 0.8 1.0 V Regulated Feedback Voltage (Note 5) l 1.182 1.2 1.218 V Feedback Voltage Line Regulation 3.5V < VCC < 9V (Note 5) 0.1 mV/V Feedback Voltage Load Regulation VITH = 1.6V (Note 5) 0.05 % VITH = 1V (Note 5) –0.05 % VFB Input Current (Note 5) 25 50 nA RUN/SS Pull Up Current VRUN/SS = 0V 1.5 3 4.5 μA VRUN/SS = 1.3V 5 15 25 μA Maximum Duty Cycle 70 78 84 % ISLMAX, Peak Slope Compensation Current 20 μA Oscillator Frequency 160 200 240 kHz Gate Drive Rise Time CLOAD = 3000pF (Note 6) 40 ns Gate Drive Fall Time CLOAD = 3000pF (Note 6) 40 ns Peak Current Sense Voltage IPRG = GND l 95 110 125 mV IPRG = Float l 165 185 210 mV IPRG = VIN l 265 295 325 mV VIN Shunt Regulator Voltage IIN = 1mA, IIN = 25mA, VRUN/SS = 0V l 9 9.3 9.6 V Default Internal Soft-Start 3.3 ms Note 1: Stresses beyond those listed under Absolute Maximum Ratings Note 3: TJ is calculated from the ambient temperature TA and power may cause permanent damage to the device. Exposure to any Absolute dissipation PD according to the following formula: Maximum Rating condition for extended periods may affect device TJ = TA + (PD • θJA) reliability and lifetime. Note 4: The dynamic input supply current is higher due to power MOSFET Note 2: The LTC3873E-5 is guaranteed to meet performance specifi cations gate charging (QG • fOSC). See Applications Information. from 0°C to 85°C. Specifi cations over the –40°C to 85°C operating Note 5: The LTC3873-5 is tested in a feedback loop which servos VFB to temperature range are assured by design, characterization and correlation the reference voltage with the ITH pin forced to the midpoint of its voltage with statistical process controls. The LTC3873I-5 is guaranteed to meet range (0.7V ≤ VITH ≤ 1.9V, midpoint = 1.3V). performance specifi cations over the full –40°C to 125°C operating Note 6: Rise and fall times are measured at 10% and 90% levels. temperature range. VCC = 5.6V. 38735fb 3
