Demonstration circuit 1820A-A/1820A-B is a step-down DC/DC converter using LTC3646/LTC3646-1 monolithic synchronous buck regulator. The input voltage range is from 4V to 40V. The output voltage range of LTC3646 is 2V to 30V, for LTC3646-1 is 0.6V to 15V. It can deliver up to 1A of output current. At light load conditions, DC1820A can operate in Burst Mode® operation to improve the efficiency. The user can choose to use internal or external compensation. The switching frequency of LTC3646/LTC3646-1 is programmable from 200kHz to 3MHz. It can be synchronized to an external clock through the MODE/ SYNC pin. The LTC3646/LTC3646-1 data sheet must be read in conjunction with this demo manual prior to working on or modifying demonstration circuit 1820A.