The TPS51220 is a dual synchronous buck regulator controller with 2 LDOs. It is optimized for 5V/3.3V system controller, enabling designers to cost effectively complete 2-cells to 4-cells notebook system power supply. The TPS51220 supports high efficiency, fast transient response and 99% duty cycle operation. It supports supply input voltages ranging from 4.5V to 28V, and output voltages from 1V to 12V. Two types of control schemes can be chosen depending on the application. Peak current mode supports stability operation with lower ESR capacitor and output accuracy. The D-CAP mode supports fast transient response. The high duty (99%) operation and the wide input/output voltage range supports flexible design for small mobile PCs and a wide variety of other applications. The fixed frequency can be adjusted from 200kHz to 1MHz by a resistor, and each channel runs 180 out of phase. The TPS51220 can also synchronize to the external clock, and the interleaving ratio can be adjusted by its duty. The TPS51220 is available in the 32 pin 5x5 QFN package and is specified from 40C to 85C.