LTC3122 15V, 2.5A Synchronous Step-Up DC/DC Converter with Output Disconnect FeaTuresDescripTion n VIN Range: 1.8V to 5.5V, 500mV After Start-Up The LTC®3122 is a synchronous step-up DC/DC converter n Output Voltage Range: 2.2V to 15V with true output disconnect and inrush current limiting. The n 800mA Output Current for VIN = 5V and VOUT = 12V 2.5A current limit along with the ability to program output n Output Disconnects from Input When Shut Down voltages up to 15V makes the LTC3122 well suited for a n Synchronous Rectification: Up to 95% Efficiency variety of demanding applications. Once started, opera- n Inrush Current Limit tion will continue with inputs down to 500mV, extending n Up to 3MHz Adjustable Switching Frequency runtime in many applications. Synchronizable to External Clock The LTC3122 features output disconnect in shutdown, n Selectable Burst Mode® Operation: 25µA IQ dramatically reducing input power drain and enabling n Output Overvoltage Protection VOUT to completely discharge. Adjustable PWM switching n Soft-Start from 100kHz to 3MHz optimizes applications for highest n <1µA IQ in Shutdown efficiency or smallest solution footprint. The oscillator n 12-Lead, 3mm × 4mm × 0.75mm Thermally can also be synchronized to an external clock for noise Enhanced DFN and MSOP Packages sensitive applications. Selectable Burst Mode operation reduces quiescent current to 25µA, ensuring high efficiency applicaTions across the entire load range. An internal soft-start limits n inrush current during start-up. RF Power n Piezo Actuators Other features include a <1µA shutdown current and ro- n Small DC Motors bust protection under short-circuit, thermal overload, and n 12V Analog Rail From Battery, 5V, or Backup Capacitor output overvoltage conditions. The LTC3122 is offered in L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks both a low profile 12-lead (3mm × 4mm × 0.75 mm) DFN and ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the package and a 12-lead thermally enhanced MSOP package. property of their respective owners. Typical applicaTion5V to 12V Synchronous Boost Converter with Output DisconnectEfficiency Curve 3.3µH 100 10 VIN 5V 90 Burst Mode OPERATION SW V 80 OUT VIN VOUT 12V POWER LOSS (W) 70 LTC3122 800mA 1 PWM OFF SD 4.7µF ON 100nF 60 BURST PWM PWM/SYNC CAP 1.02M 50 RT FB 22µF 40 EFFICIENCY (%) 0.1 V 30 CC VC 113k PWM POWER LOSS 20 SGND PGND 210k 57.6k 10pF 10 4.7µF 390pF 0 0.01 0.01 0.1 1 10 100 1000 LOAD CURRENT (mA) 3122 TA01b 3122 TA01a 3122fa For more information www.linear.com/LTC3122 1 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 Applications Package Description Typical Application Related Parts
