LTC1709-8 Datasheet | Linear Technology

Final Electrical Specifications LTC1709-8/LTC1709-9 2-Phase, 5-Bit VID, Current Mode, High Efficiency, Synchronous Step-Down Switching Regulators May 2000 Features s DESCRIPTIO s s s s s s s s s s s s s U APPLICATIO S s s s s Single Controller Operates Two Output Stages: Antiphase Reducing Required Input Capacitance and Power Supply Induced Noise Two 5-Bit Desktop VID Codes: LTC1709-8 For VRM8.4 (VOUT from 1.3V to 3.5V) LTC1709-9 For VRM9.0 (VOUT from 1.1V to 1.85V) Current Mode Control Ensures Best Current Sharing True Remote Sensing Differential Amplifier Power Good Output Indicator OPTI-LOOPTM pensation Minimizes COUT Programmable Fixed Frequency: 150k Hz to 300k Hz ±1% Output Voltage Accuracy Wide VIN Range: 4V to 36V Operation Adjustable Soft-Start Current Ramping Internal Current Foldback and Short-Circuit Shutdown Overvoltage Soft Latch Eliminates Nuisance Trips Low Shutdown Current: 20µA Available in 36-Lead SSOP Package The LTC®1709-8/LTC1709-9 are 2-phase, VID programmable, synchronous step-down switching regulator controllers that drive two all N-channel external power MOSFET stages in a fixed frequency architecture. The 2-phase controller drives its two output stages out of phase at frequencies up to 300k Hz to minimize the RMS ripple currents in both input and output capacitors. The 2-phase technique effectively multiplies the fundamental frequency by two, improving transient response while operating each channel at an optimum frequency for efficiency. Thermal design is also simplified. An internal differential amplifier provides true remote sensing of the regulated supply’s positive and negative output terminals as required for high current applications. The RUN/SS pin provides soft-start and optional timed, short-circuit shutdown. Current foldback limits MOSFET dissipation during short-circuit conditions when the overcurrent latchoff is disabled. OPTI-LOOP pensation allows the transient response to be optimized for a wide range of output...