LTC1709-9

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 Compensation Minimizes COUT Programmable Fixed Frequency: 150kHz to 300kHz ±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 300kHz 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. Th...