Microsemi Corp. Special Purpose Regulators LX1665ACDW

The LX1665ACDW is a monolithic switching regulator controller IC designed for high-performance adjustable power supply applications, particularly for advanced microprocessors. It features a programmable synchronous rectifier driver, allowing the main output voltage to be adjusted from 1.3V to 3.5V using a 5-bit code, which conforms to Intel specifications. The device supports fast transient response and high efficiency, typically achieving 85-90% efficiency even under loads exceeding 10A. The LX1665ACDW includes over-voltage protection (OVP) and a power good flag, which are essential for applications requiring output voltage monitoring and protection. It operates with a supply voltage of up to 25V and has a thermal resistance of 60¬8C/W in the 18-pin DIP package. The IC is suitable for various applications, including Pentium II and Deschutes processor supplies, and can drive either synchronous or non-synchronous output stages. Engineers considering this product should note its capability to eliminate the need for expensive current sense resistors due to its current-sensing mechanism, which can utilize PCB trace resistance or the parasitic resistance of the main inductor. The device also offers soft-start capability and a modulated, constant off-time architecture for simplified system design.