LTC3785 elecTrical characTerisTics The l denotes the specifications which apply over the full operating junctiontemperature range, otherwise specifications are at TA = 25°C. VIN = ISVOUT = VDRV = VBST1 = VBST2 = 3.6V, RT = 49.9k, RILSET = 59k. PARAMETERCONDITIONSMINTYPMAXUNITS BG1, BG2 Rise Time CLOAD = 3300pF (Note 3) 20 ns TG1, TG2 Fall Time CLOAD = 3300pF (Note 3) 20 ns BG1, BG2 Fall Time CLOAD = 3300pF (Note 3) 20 ns Buck Driver Nonoverlap Time TG1 to BG1 100 ns Boost Driver Nonoverlap Time TG2 to BG2 100 ns Note 1: Stresses beyond those listed under Absolute Maximum Ratings to meet performance specifications over the full –40°C to 125°C operating may cause permanent damage to the device. Exposure to any Absolute junction temperature range. Maximum Rating condition for extended periods may affect device Note 3: Specification is guaranteed by design and not 100% tested in reliability and lifetime. production. Note 2: The LTC3785E is guaranteed to meet performance specifications Note 4: Current measurements are performed when the outputs are not from 0°C to 85°C. Specifications over the –40°C to 85°C operating switching. junction temperature range are assured by design, characterization and Note 5: The IC is tested in a feedback loop to make the measurement. correlation with statistical process controls. The LTC3785I is guaranteed Typical perForMance characTerisTics TA = 25°C, unless otherwise noted.Li-Ion to 3.3V EfficiencyTwo Li-Ion to 7V EfficiencyLi-Ion/9V to 5V VOUT Efficiencyvs Load Currentvs Load Currentvs Load Current 100 100 100 Burst Mode Burst Mode 90 OPERATION 90 Burst Mode 90 OPERATION OPERATION 80 80 80 70 70 70 60 FIXED FIXED FIXED FREQUENCY 60 FREQUENCY 60 FREQUENCY 50 50 50 V 40 40 40 IN = 9V EFFICIENCY (%) VIN = 4.2V V EFFICIENCY (%) VIN = 8.4V EFFICIENCY (%) IN = 4.2V 30 VIN = 3.6V 30 VIN = 7.2V 30 VIN = 3.6V VIN = 3V VIN = 5.4V VIN = 2.7V 20 MOSFET Si7940 20 MOSFET Si7940 20 MOSFET Si7940 10 L = 4.7µH WURTH WE-PD 10 L = 5.6µH MSS1260 10 L = 5.6µH MSS1260 fOSC = 500kHz fOSC = 430kHz fOSC = 430kHz 0 0 0 0.0001 0.001 0.01 0.1 1 10 0.0001 0.001 0.01 0.1 1 10 0.0001 0.001 0.01 0.1 1 10 LOAD CURRENT (A) LOAD CURRENT (A) LOAD CURRENT (A) 3785 G01 3785 G02 3785 G03 Burst Mode RippleLine Transient ResponseVOUT Load Transient VOUT VOUT VOUT 500mV/ 200mV/ 50mV/DIV DIV DIV AC COUPLED VIN INDUCTOR 3V TO I CURRENT 8.5V LOAD 10mA TO 2A 1A/DIV V 3785 G04 3785 G05 3785 G06 OUT = 3.3V 5µs/DIV ILOAD = 300mA 500µs/DIV VIN = 3.6V 100µs/DIV COUT = 100µF VOUT = 5V VOUT = 3.3V COUT = 100µF COUT = 100µF 3785fc Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Application Package Description Revision History Typical Application Related Parts