Dual, 2-Phase Synchronous DC/DC Controller with Pin Selectable Outputs

The LTC3865/LTC3865-1 are high performance dual synchronous step-down DC/DC switching regulator controllers that drive all N-channel synchronous power MOSFET stages. A constant frequency current mode architecture allows a phase-lockable frequency of up to 770kHz. Power loss and 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. Independent track/soft-start pins for each controller ramp the output voltage 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, and continuous inductor current mode. The output voltages can be precisely programmed by pin strapping or external resistors.

The LTC3865/LTC3865-1 are available in low profile (5mm × 5mm) 32-pin QFN and 38-Lead thermally enhanced TSSOP packages.

Applications

* DC Power Distribution Systems

* Dual, 180° Phased Controllers

* 2-Pin VID Output Voltage Programming from 0.6V to 5V

* High Efficiency: Up to 95%

* RSENSE or DCR Current Sensing

* Phase-Lockable Fixed Frequency 250kHz to 770kHz

* Adjustable Current Limit

* Dual N-Channel MOSFET Synchronous Drive

* Wide VIN Range: 4.5V to 38V Operation

* Adjustable Soft-Start Current Ramping or Tracking

* Output OV Protection With Reverse Current Limit

* Power Good Output Voltage Monitor

* 32-Pin 5mm × 5mm QFN and 38-Lead TSSOP Packages