by Susan Nordyk @ edn.com:
Housed in a tiny 3×3-mm QFN package, the MIC24046-H synchronous step-down regulator from Micrel offers efficiency of greater than 90% peak and pin-selectable output voltage, switching frequency, and current limit. A wide input voltage range of 4.5 V to 19 V makes the part useful for distributed 12-V point-of-load applications.
The switching frequency of the MIC24046-H can be programmed to one of three options: 400 kHz, 565 kHz, or 790 kHz. Programmable output-voltage choices include 0.7 V, 0.8 V, 0.9 V, 1.0 V, 1.2 V, 1.5 V, 1.8 V, 2.5 V, and 3.3 V, while an internal divider is used to achieve ±1% voltage-output accuracy. The current limit of the regulator can be programmed to 3 A, 4 A, or 5 A.
Buck converter is pin-programmable – [Link]