DESCRIPTION
The LTC®1929 is a 2-phase, single output, synchronous step-down current mode switching regulator controller that drives N-channel external power MOSFET stages in a phase-lockable 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. Thermal design is also simplified.

FEATURES
■ 2-Phase Single Output Controller
■ Reduces Required Input Capacitance and Power Supply Induced Noise
■ Current Mode Control Ensures Current Sharing
■ Phase-Lockable Fixed Frequency: 150kHz to 300kHz
■ True Remote Sensing Differential Amplifier
■ OPTI-LOOPTM Compensation Improves Transient Response
■ ±1% Output Voltage Accuracy
■ Wide VIN Range: 4V to 36V Operation
■ Very Low Dropout Operation: 99% Duty Cycle
■ Adjustable Soft-Start Current Ramping
■ Internal Current Foldback
■ Short-Circuit Shutdown Timer with Defeat Option
■ Overvoltage Soft-Latch Eliminates Nuisance Trips
■ Available in 28-Lead SSOP Package

APPLICATIONS
■ Desktop Computers
■ Internet/Network Servers
■ Large Memory Arrays
■ DC Power Distribution Systems