Camarillo, Calif. - Semtech's SC1404 is a highly integrated multi-output PWM controller for notebook PCs that's designed to simplify the power architecture, reduce component count and lower overall system costs. It integrates four regulators, two of which are synchronous buck (switching) types that deliver 3.3 and 5 volts (from a 6- to 30-volt input) to drive external power MOSFETs. Those controllers operate out-of-phase to minimize input ripple, thus reducing input-capacitance filter requirements by as much as one-half. The SC1404 also contains two linear regulators to power general system housekeeping functions; one runs from the battery and delivers 5 volts at 50 mA, and the other is a 12-volt, 200 mA device that's powered by the chip's 5-volt switching regulator.
The chip features the company's Virtual Current Sense technology, which along with an external error amp achieves enhanced stability and DC accuracy over a wide range. Operational features include a line and load regulation to within ± 1 percent; and over-current, over-voltage, and over-temperature protection, and under-voltage lockout.
Control features include soft start, power-up sequencing, and frequency synchronization. The user can select 200 kHz operation for best efficiency or 300 kHz operation for minimized ripple, fastest transient response, and/or smallest output filter component size. The SC1404 features very low quiescent power consumption (6 mW, typical); standby-mode quiescent current (switchers disabled) is 250 microamps and shutdown-mode current is 4 microamps. The chip enters the power-save mode when load current falls below an externally programmable threshold.
The SC1404 is available now in production quantities and is priced at $4.05 each in 1,000-pc quantities for the TSSOP-28 package, and $3.95 for the SSOP-28 package. Evaluation kits and samples are available.