Demonstration Circuit 616 is a synchronous, 4-phase boost converter using the LTC3425. It is capable of operating below 1V input. DC616A is set for 3.3V output. DC616B is set for 5V output. On each demo board, the left circuit gives higher efficiency and current rating; while the right circuit has smaller size and lower cost. The switching frequency is set at 1MHz per phase, minimizing inductor and capacitor size. A single resistor at RT pin sets the frequency. If desired, the LTC3425 can be synchronized to an external clock. Long wires run from input sources (such as wall adaptors) can cause large voltage spikes during initial plugin. C5 and C15 are installed on DC616 to damp the possible voltage spikes. They are not required for applications where input source is close to the regulator. Please refer to Application Note 88 for details.