IRU3034

Data Sheet No. PD94148 revA IRU3034 & (PbF) 8-PIN PWM SWITCHER CONTROLLER IC WITH CURRENT LIMITING DESCRIPTION The IRU3034 IC provides a low cost switching controller with true short circuit protection all in a compact 8-pin surface mount package, providing a low cost switching solution for dual supply processor applications that require switching regulator for the 3.3V supply such as the applications with AGP on-board. Typically in these applications, a dual supply regulator converts 5V to 3.3V for I/O supply and a jumper programmable supply of 1.25V to 3.5V for Core supply. The IC uses an internal regulator generated from the 12V supply to power the controller as well as the 12V supply to drive the power MOSFET, allowing a low cost N-channel MOSFET to be used. The IC also includes an error comparator for fast transient response, a precise voltage reference for setting the output voltage as well as a direct drive of the MOSFET for the minimum part count. FEATURES 8-Pin SOIC switching controller with HICCUP current limiting reduces diode power dissipation to less than 1% of normal operation Soft-Start capacitor allows for smooth output voltage ramp up On-Board MOSFET Driver Fastest transient response of any controller method. (0 to 100% Duty Cycle in 100ns) 1% Internal Voltage Reference Internal Under-Voltage Lockout protects MOSFET during start-up APPLICATIONS Dual supply low voltage processor applications, such as: P55C, CYRIX M2, POWER PC and AMD K6 Simple 5V to 3....