Datasheet Linear Technology LTC3850IUFD#TRPBF
Dual, 2-Phase Synchronous Step-Down Switching Controller
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FEATURES LTC3850/LTC3850-1 Dual, 2-Phase Synchronous Step-Down Switching Controller DESCRIPTION
The LTC®3850 is a high performance dual synchronous step-down switching regulator controller that drives all N-channel power MOSFET stages. A constant-frequency current mode architecture allows a phase-lockable frequency of up to 780kHz. Power loss and supply noise are minimized by operating the two controller output stages out of phase. OPTI-LOOP® compensation allows the transient response to be optimized over a wide range of output capacitance and ESR values. The LTC3850 features a precision 0.8V reference and a power good output indicator. A wide 4V to 24V (28V maximum/30V for LTC3850I) input supply range encompasses most battery chemistries and intermediate bus voltages. Independent TK/SS pins for each controller ramp the output voltages during start-up. Current foldback limits MOSFET heat dissipation during short-circuit conditions. The MODE/PLLIN pin selects among Burst Mode® operation, pulse-skipping mode, or continuous inductor current mode and allows the IC to be synchronized to an external clock. The LTC3850 is available in low profile 28-pin 4mm × 4mm, 4mm × 5mm QFN and narrow SSOP packages. n Dual, 180° Phased Controllers Reduce Required Input Capacitance and Power Supply Induced Noise High Efficiency: Up to 95% RSENSE or DCR Current Sensing ±1% 0.8V Output Voltage Accuracy Phase-Lockable Fixed Frequency 250kHz to 780kHz Supports Pre-Biased Output Dual N-Channel MOSFET Synchronous Drive Wide VIN Range: 4V to 24V (30V for LTC3850I) Operation Adjustable Soft-Start Current Ramping or Tracking Foldback Output Current Limiting Output Overvoltage Protection Power Good Output Voltage Monitor 28-Pin 4mm × 4mm, 4mm × 5mm QFN and Narrow SSOP Packages APPLICATIONS Notebook and Palmtop Computers Portable Instruments Battery-Operated Digital Devices DC Power Distribution Systems L, LT, LTC, LTM, OPTI-LOOP and Burst Mode are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents, including 5481178, 5705919, 5929620, 6100678, 6144194, 6177787, 6304066, 6580258. TYPICAL APPLICATION
High Efficiency Dual 3.3V/2.5V Step-Down Converter
4.7µF VIN PGOOD INTVCC 0.1µF 2.2µH TG1 BOOST1 SW1 BG1 2.2k 500kHz ILIM 0.1µF SENSE1+ RUN1 SENSE1 VFB1 ITH1 TK/SS1 0.1µF SGND TG2 BOOST2 SW2 BG2 PGND FREQ/PLLFLTR SENSE2+ RUN2 SENSE2 VFB2 ITH2 TK/SS2 0.1µF 10nF 10k 0.1µF 43.2k 220pF 15k 20k
38501 TA01 22µF 50V VIN 7V TO 24V Efficiency
100 VIN = 12V 95 VOUT = 3.3V 10000 EFFICIENCY 90 0.1µF 2.2µH ...
Power Management > Switching Regulator > Step-Down (Buck) Regulators > Multiple Output Buck
Other Names: LTC3850IUFDTRPBF, LTC3850IUFD TRPBF
Docket:FEATURES LTC3850/LTC3850-1 Dual, 2-Phase Synchronous Step-Down Switching Controller DESCRIPTION
The LTC®3850 is a high performance dual synchronous step-down switching regulator controller that drives all N-channel power MOSFET stages. A constant-frequency current mode architecture allows a phase-lockable frequency of up to 780kHz. Power loss and supp...
- Series: LTC3850, LTC3850-1 (17)