LTC1628-SYNC

U U LTC1628-SYNC High Efficiency, 2-Phase Synchronous Step-Down Switching Regulator FEATURES ■ Out-of-Phase Controllers Reduce Required Input Capacitance and Power Supply Induced Noise ■ OPTI-LOOP® Compensation Minimizes COUT ■ Dual N-Channel MOSFET Synchronous Drive ■ ±1% Output Voltage Accuracy ■ Power Good Output Voltage Monitor ■ Phase-Lockable Fixed Frequency 150kHz to 300kHz ■ Wide VIN Range: 3.5V to 36V Operation ■ Very Low Dropout Operation: 99% Duty Cycle ■ Adjustable Soft-Start Current Ramping ■ Foldback Output Current Limiting ■ Latched Short-Circuit Shutdown with Defeat Option ■ Output Overvoltage Protection ■ Remote Output Voltage Sense ■ Low Shutdown IQ: 20µA ■ 5V and 3.3V Standby Regulators ■ Selectable Constant Frequency or Burst Mode® Operation ■ Small 28-Lead SSOP Package U APPLICATIO S ■ Notebook and Palmtop Computers, PDAs ■ Telecom Systems ■ Battery-Operated Digital Devices ■ DC Power Distribution Systems DESCRIPTIO The LTC®1628-SYNC is a high performance dual stepdown switching regulator controller that drives all N-channel synchronous power MOSFET stages. A constant frequency current mode architecture allows phaselockable frequency of up to 300kHz. Power loss and noise due to the ESR of the input capacitors 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 precision 0.8V reference and power good outp...