描述 Description

Features:
? 5-Bit Programmable Output For CPU CoreSupply
? Power Solution For Pentium II Processors
? No Sense Resistor Required For Short-CircuitCurrent Limiting
? Soft-Start And Hiccup-Mode CurrentLimiting Functions· Modulated Constant Off-Time ControlMechanism For Fast Transient Response AndSimple System Design
? Power Good Flag
? Over-Voltage Pin Can Drive SCR Crowbar OrTurn Off Signal Silver-Box Power Supply
? Digital-Compatible Inputs (Including VID Pins)The LX1669 is a Monolithic Switching Regulator Controller IC designed to provide a low cost, high performance adjustable power supply for advanced microprocessors and other applications requiring a very fast transient response and a high degree of accuracy. It provides a programmable switching regulator output suitable for powering Pentium ? II and other processors.Programmable Synchronous Rectifier Driver for CPU Core. The main output is adjustable from 1.3 to 3.5V using a TTL-compatible 5-bit digital code to meet Intel specifications. The IC can read the signal from a DIP-switch, hardwired to Pentium II processor’s pins or from soft-ware. The 5-bit code adjusts the output voltage between 1.30 and 2.05V in 50mV increments, and between 2.0 and 3.5V in 100mV increments. The device can drive dual MOSFET’s resulting in typical efficiencies of 85 – 90%, even with loads in excess of 10A.Short-circuit Current Limiting without Expensive Current Sense Resistors. The current sensing mechanism can use a PCB trace resistance or the parasitic resistance of the main inductor. For applications requiring a high degree of accuracy, a conventional sense resistor can be used.Ultra-Fast Transient Response Reduces System Cost. The fixed frequency modulated off-time architecture results in the fastest transient response for a given inductor.Small Package Size. The LX1669 is available in an economical 16-pin narrow body SOIC package.??ROHS