SC1173

POWER MANAGEMENT Description SC1172 & SC1173 Programmable Synchronous DC/DC Converter with LDO Controller Features The SC1172/3 combines a synchronous voltage mode controller with a low-dropout linear regulator providing most of the circuitry necessary to implement two DC/DC converters for powering advanced microprocessors such as Pentium® II . The SC1172/3 switching section features an integrated 5 bit D/A converter, pulse by pulse current limiting, integrated power good signaling, and logic compatible shutdown. The SC1172/3 switching section operates at a fixed frequency of 200kHz, providing an optimum compromise between size, efficiency and cost in the intended application areas. The integrated D/A converter provides programmability of output voltage from 2.0V to 3.5V in 100mV increments and 1.30V to 2.05V in 50mV increments with no external components. The SC1172/3 linear section is a low dropout regulator. The SC1172 supplies 1.5V for GTL bus , the SC1173 features an adjustable LDO voltage. u Synchronous design, enables no heatsink solution. u 95% efficiency (switching section). u 5 bit DAC for output programmability. u On chip power good function. u Designed for Intel Pentium® ll VRM8.1 requirements. u 1.5V or Adjustable @ 1% for linear section. Applications u Pentium® ll microprocessor supplies u Flexible motherboards u 1.3V to 3.5V microprocessor supplies u Programmable triple power supplies Typical Application Circuit 12V 5V + 1500uF x2 PWRGOOD VID0 VID1 VID2 V...