DC1820A-A

DEMO MANUAL DC1820A-A/DC1820A-B LTC3646/LTC3646-1 High Efficiency Low Quiescent Current Step-Down Converter DESCRIPTION Demonstration circuit 1820A-A/1820A-B is a step-down be synchronized to an external clock through the MODE/ DC/DC converter using LTC3646/LTC3646-1 monolithic SYNC pin. The LTC3646/3646-1 data sheet must be read synchronous buck regulator. The input voltage range is in conjunction with this demo manual prior to working on from 4V to 40V. The output voltage range of LTC3646 is or modifying demonstration circuit 1820A. 2V to 30V, for LTC3646-1 is 0.6V to 15V. It can deliver up Design files for this circuit board are available at to 1A of output current. At light load conditions, DC1820A DEMO MANUAL DC1820A-A/DC1820A-B QUICK START PROCEDURE Demonstration circuit 1820A is an easy way to evaluate 3. Turn on the power at the input. Increase V to 12V (Do IN the performance of the LTC3646/LTC3646-1. Please refer not hot-plug the input supply or apply more than the to Figure 1 for proper measurement equipment setup and rated maximum voltage of 40V to the board or the follow the procedure below: part may be damaged). The output voltage should be regulated and deliver the selected output voltage 2%. 1. Place jumpers in the following positions for a typical application: 4. Vary the input voltage from 4V to 40V and adjust the load current from 0A to 1A. Observe the output voltage MODE EXTVCC RUN V SELECT OUT regulation, ripple voltage, efficiency, and other param- FCC GND ON 3.3V eters. 2. With power off, connect the input power supply, load 5. To measure input or output ripple, please refer to Figure 2 and meters as shown in Figure 1. Preset the load to 0A for proper measurement setup. and V supply to be 0V. IN + + + V IN + + LOAD + Figure 1. Proper Measurement Equipment Setup dc1820aabf 2