ML4901

April 1997 PRELIMINARY ML4901 High Current Synchronous Buck Controller GENERAL DESCRIPTION The ML4901 high current synchronous buck controller has been designed to provide high efficiency DC/DC conversion for next generation processors such as the Pentium® Pro from Intel®. The ML4901 controller, when combined with 2 external MOSFETs, generates output voltages between 2.1V and 3.5V from a 12V supply. The output voltage is selected via an internal 4-bit DAC. Output currents in excess of 14A can be attained at efficiencies greater than 90%. The ML4901 can be enabled/disabled via the SHDN pin. While disabled, the output of the regulator is completely isolated from the circuit’s input supply. The ML4901 employs fixed-frequency PWM control combined with a dual mode control loop to provide excellent load transient response. FEATURES s Designed to meet Pentium® Pro power supply requirements DC regulation to +1% maximum Proprietary circuitry provides transient response of +5% maximum over 300mA to 14A load range Programmable output voltage (2.1V to 3.5V) is set by an onboard 4-bit DAC Synchronous buck topology for maximum power conversion efficiency Fixed frequency operation for easier system integration Integrated antishoot-through logic, short circuit protection, and UV lockout Shutdown control provides load isolation s s s s s s s BLOCK DIAGRAM (Pin Configuration Shown for 16-Pin SOIC Version) 15 VDD + 10.4V PROTECT 16 – UVLO + – P DRV 14 4.4V CONTROL LOGIC N DRV 1...