Demonstration circuit 561 is a high current stepdown PolyPhaseTM converter featuring the LTC®3731 three-phase synchronous buck controller. To minimize the supply footprint size and improve the thermal performance, the 5mm x 5mm QFN package LTC3731CUH controller is used. The switching frequency of the LTC3731 is in the 250kHz to 600kHz range. The input voltage is from 10V to 14V and output is 1.5V. An optional VID controller circuit is available on both DC561A-A and DC561A-B demo circuits for output voltage programming. DC561A-A can provide up to 180A output current with a 12-phase buck circuit, while DC561A-B is a 6-phase buck converter with up to 90A output current. Optional 0.1% external voltage reference and external OP-AMP compensation circuits are also available on DC561A-A and DC561A-B for accurate voltage regulation and best transient response. Additional MOSFETs can be populated for higher output current.