Digitally programmable buck regulator offers ultra-low quiescent current

San Jose, Calif. — Fairchild Semiconductor has introduced the FAN5355 digitally programmable buck regulator that gives system design engineers a highly efficient power management solution for new dynamic voltage scaling (DVS) platforms used in today's cell phones, portable media players (PMPs) and other portable applications.

The FAN5355, an 800 mA/1000 mA 3-MHz buck converter, features a proprietary ultra-fast architecture that consumes very low quiescent current while delivering an ultra-fast transient response. Even with a typical quiescent current in PFM mode of 37 uA, the FAN5355 is said to provide best-in-class transient response, making the application more resilient to unexpected fluctuations in load.

In addition, this architecture creates lower ripple during PFM mode, reducing system noise and significantly improving light load efficiency to 85 percent even at loads of only 1 mA. For more moderate to heavy loads, careful optimization of the power train contributes to a conversion efficiency of more than 90 percent during PWM mode, Fairchild said.

The FAN5355 is equipped with an I2C interface allowing the system to dynamically adjust the digital core's power supply voltage based on the processor workload. Typical cores benefiting from DVS are application processors, graphics processors and DSPs in mobile applications. By tailoring the power-supply voltage level to the processing state of the core, energy consumption is reduced leading to longer battery life, Fairchild said.

In order to maximize the effectiveness of the DVS, the FAN5355's digitally programmable output voltage offers a range of 0.75 V to 1.975 V and can be adjusted in 12.5 mV increments. The FAN5355 is available in 3 x 3-mm MLP packaging and 12 bump, 0.5-mm pitch WL-CSP packaging.

The FAN5355 utilizes lead-free (Pb-free) terminals and has been characterized for moisture sensitivity in accordance with the Pb-free reflow requirements of the joint IPC/JEDEC standard J-STD-020. The devices are RoHS compliant.

Pricing: The FAN5355 in a MLP package is priced at $0.84; in WL-CSP packaging at $0.94, in quantities of 1,000.
Availability: Samples are available now. Delivery is eight weeks ARO.
Datasheet: FAN5355

Fairchild Semiconductor ,

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