SC1182

PROGRAMMABLE SYNCHRONOUS DC/DC CONVERTER, DUAL LOW DROPOUT REGULATOR CONTROLLER August 25, 1998 SC1182/3 TEL:805-498-2111 FAX:805-498-3804 WEB:http://www.semtech.com DESCRIPTION The SC1182/3 combines a synchronous voltage mode controller with two low-dropout linear regulators providing most of the circuitry necessary to implement three DC/DC converters for powering advanced ® microprocessors such as Pentium II (Klamath) or Deschutes. The SC1182/3 switching section features an integrated 5 bit D/A converter, pulse by pulse current limiting, integrated power good signaling, and logic compatible shutdown. The SC1182/3 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 SC1182/3 linear sections are low dropout regulators. The SC1182 supplies 1.5V for GTL bus and 2.5V for non-GTL I/O. For the SC1183 both LDO’s are adjustable. FEATURES Synchronous design, enables no heatsink solution 95% efficiency (switching section) 5 bit DAC for output programmability On chip power good function ® Designed for Intel Pentium ll VRM8.1 requirements 1.5V, 2.5V or Adj. @ 1% for linear section APPLICATIONS Pentium ll or Deschutes microprocessor supplies Flexible motherboards 1.3V to 3.5V micr...