SC1155

PROGRAMMABLE SYNCHRONOUS DC/DC HYSTERETIC CONTROLLER WITH VRM 9.0 VID RANGE PRELIMINARY - August 7, 2000 SC1155 DESCRIPTION The SC1155 is a synchronous-buck switch-mode controller designed for use in single ended power supply applications where efficiency is the primary concern. The controller is a hysteretic type, with a user selectable hysteresis. The SC1155 is ideal for implementing DC/DC converters needed to power advanced microprocessors such as Pentium® llI and Athlon®, in both single and multiple processor configurations. Inhibit, under-voltage lockout and soft-start functions are included for controlled power-up. SC1155 features include an integrated 5 bit D/A converter, temperature compensated voltage reference, current limit comparator, over-current protection, and an adaptive deadtime circuit to prevent shoot-through of the power MOSFET during switching transitions. Power good signaling, logic compatible shutdown, and over-voltage protection are also provided. The integrated D/A converter provides programmability of output voltage from 1.1V to 1.85V in 25mV increments. The SC1155 high side driver can be configured as either a grounded reference or as a floating bootstrap driver. The high and low side MOSFET drivers have a peak current rating of 2 amps. FEATURES = Programmable hysteresis = 5 bit DAC programmable output (1.1V-1.85V) = On-chip power good and OVP functions = Designed to meet latest Intel specifications = Up to 95% efficiency = +1% voltage tole...