LTC3547 TheELECTRICAL CHARACTERISTICS ● denotes the specifi cations which apply over the full operatingtemperature range, otherwise specifi cations are at TA = 25°C. VCC = 3.6V, unless otherwise noted.SYMBOLPARAMETERCONDITIONSMINTYPMAXUNITS RDS(ON) Channel 1 (Note 4) Top Switch On-Resistance VIN = 3.6V, ISW = 100mA 0.8 1.05 Ω Bottom Switch On-Resistance VIN = 3.6V, ISW = 100mA 0.75 1.05 Ω Channel 2 (Note 4) Top Switch On-Resistance VIN = 3.6V, ISW = 100mA 0.8 1.05 Ω Bottom Switch On-Resistance VIN = 3.6V, ISW = 100mA 0.75 1.05 Ω ISW(LKG) Switch Leakage Current VIN = 5V, VRUN = 0V 0.01 1 µA tSOFTSTART Soft-Start Time VFB From 10% to 90% Full-Scale 0.450 0.650 0.850 ms VRUN RUN Threshold High ● 0.4 1 1.2 V IRUN RUN Leakage Current ● 0.01 1 µA VBURST Output Ripple in Burst Mode Operation VOUT = 1.5V, COUT = 4.7µF 20 mVP-P Note 1: Stresses beyond those listed under Absolute Maximum Ratings Note 4: The DFN switch on-resistance is guaranteed by correlation to may cause permanent damage to the device. Exposure to any Absolute wafer level measurements. Maximum Rating condition for extended periods may affect device Note 5: Guaranteed by long term current density limitations. reliability and lifetime. Note 6: This IC includes overtemperature protection that is intended Note 2: The LTC3547E is guaranteed to meet specifi ed performance to protect the device during momentary overload conditions. Junction from 0°C to 85°C. Specifi cations over the –40°C and 85°C operating temperature will exceed 125°C when overtemperature protection is active. temperature range are assured by design, characterization and correlation Continuous operation above the specifi ed maximum operating junction with statistical process controls. temperature may impair device reliability. Note 3: Dynamic supply current is higher due to the internal gate charge being delivered at the switching frequency. WUTYPICAL PERFOR A CE CHARACTERISTICSBurst Mode OperationEffi ciency vs Input VoltageSupply Current vs Temperature 100 60 VOUT = 1.8V RUN1 = RUN2 = VIN SW, AC ILOAD = 0A COUPLED 90 55 5V/DIV 50 80 µA) VOUT 50mV/DIV 45 70 VIN = 5.5V 40 IL 60 50mA/DIV 35 EFFICIENCY (%) 50 IOUT = 0.1mA SUPPLY CURRENT ( V I 30 IN = 2.7V OUT = 1mA 3547 G01 I 2.5µs/DIV 40 OUT = 10mA I 25 V OUT = 100mA IN = 3.6V I V OUT = 300mA OUT = 1.8V 30 20 ILOAD = 20mA 2.5 3 3.5 4 4.5 5 5.5 –50 –25 0 25 50 75 100 VIN (V) TEMPERATURE (ºC) 3547 G02 3547 G03 3547fa 3