LTC3839 Fast, Accurate, 2-Phase, Single-Output Step-Down DC/DC Controller with Differential Output Sensing FEATURESDESCRIPTION n Wide VIN Range: 4.5V to 38V, VOUT: 0.6V to 5.5V The LTC®3839 is a 2-phase, single-output PolyPhase® n ±0.67% Output Voltage Accuracy Over Temperature, synchronous step-down switching regulator controller Differential Output Voltage Sensing, Allowing Up to that drives all N-channel power MOSFETs. The controlled ±500mV Line Loss at Remote Ground on-time, valley current mode control architecture allows for n Controlled On-Time, Valley Current Mode Control fast transient response and constant frequency switching n Fast Load Transient Response in steady-state operation, independent of VIN, VOUT and n Detect Transient (DTR) Reduces VOUT Overshoot load current. Its load-release transient detection feature n Frequency Programmable from 200kHz to 2MHz, significantly reduces overshoot at low output voltages. Synchronizable to External Clock Differential output voltage sensing, along with a preci- n tON(MIN) = 30ns, tOFF(MIN) = 90ns sion internal reference, offers an accurate ±0.67% output n Up to 12-Phase Operation regulation, even if the remote output ground deviates from n RSENSE or Inductor DCR Current Sensing local ground by ±500mV. n Overvoltage Protection and Current Limit Foldback n Power Good Output Voltage Monitor The switching frequency can be programmed from 200kHz n Output Voltage Tracking and Adjustable Soft Start-Up to 2MHz with an external resistor and can be synchronized n Thermally Enhanced 32-Pin (5mm × 5mm) QFN to an external clock. Very low tON and tOFF times allow for Package near 0% and near 100% duty cycles, respectively. Volt- age tracking soft start-up and multiple safety features are provided. APPLICATIONS L, LT, LTC, LTM, PolyPhase, OPTI-LOOP, Linear Technology and the Linear logo are registered trademarks and Hot Swap and Stage Shedding are trademarks of Linear Technology n Distributed Power Systems Corporation. All other trademarks are the property of their respective owners. Protected by U.S. n Point-of-Load Converters Patents, including 5481178, 5847554, 6580258, 6304066, 6476589, 6774611. n Computing Systems n Data Communication Systems TYPICAL APPLICATION3.3V/25A Output, 2MHz Step-Down Converter (Refer to Figure 20 for Full Design) VIN 4.5V TO 14V Efficiency/Power Loss SENSE1– SENSE2– 100 10 VIN = 5V SENSE1+ SENSE2+ DISCONTINUOUS MODE VIN INTVCC 90 8 TG1 TG2 POWER LOSS (W) LTC3839 V SW1 SW2 OUT 0.3µH 0.3µH 80 FORCED 6 CONTINUOUS 3.3V BOOST1 BOOST2 MODE 25A 0.1µF 0.1µF 45.3k + 70 4 DRV 100µF CC1 DRVCC2 EFFICIENCY (%) ×6 BG1 BG2 10k 4.7µF 60 2 PGND LOSS MODE/PLLIN FORCED CM LOSS VOUTSENSE+ CLKOUT 50 DCM 0 VOUTSENSE– 0.1 1 10 100 PHASMD TRACK/SS LOAD CURRENT (A) RUN ITH 3839 TA01b 18.7k DTR RT SGND 3839 TA01a 3839fa 1 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Typical Performance Characteristics Pin Functions Functional Diagram Operation Typical Applications Typical Application Related Parts
