DEMO MANUAL DC2113A LTC3649, 60V, Low I Q Monolithic High Efficiency Step-Down Regulator DESCRIPTION Demonstration circuit 2113A is a high input voltage, high The DC2113A consumes less than 15A of quiescent cur- efficiency synchronous monolithic buck converter featur- rent during shutdown and it consumes less than 440A at ing the LTC 3649. The DC2113A has wide input voltage no load conditions in Burst Mode operation. The DC2113A range from 3.1V up to 60V. The output voltage of the has a standard operating frequency of 500kHz, but can be DC2113A can be set as to 3.3V or 5V. However, USER adjusted in a range between 300kHz and as high as 3MHz. SELECT option of DC2113A allows output voltage to be DC2113A is a monolithic step-down converter, LTC3649 as high as input voltage minus 0.5V, with certain modi- integrates top and bottom N-channel MOSFETs, signifi- fications. DC2113A is capable of delivering up to 4A of cantly reducing circuit footprint. DC2113A was designed output current. DC2113A supports three operation modes: to support multiple footprints of input/output capacitors Fixed-Frequency modulation, Burst Mode operation and inductor to accommodate variety of applications. and the user can synchronize it with external clock also. The data sheet of LTC3649 gives a complete description Fixed-Frequency mode of operation maximizes the output functionality of this regulator also contains operation and current, reduces output voltage ripple, and yields a low application information and must be read in conjunction noise switching spectrum. Burst Mode operation employs with this demo board manual for DC2113A. a variable frequency switching algorithm that minimizes the Design files for this circuit board are available at no-load input quiescent current and improves efficiency DEMO MANUAL DC2113A QUICK START PROCEDURE Demonstration circuit 2113A is easy to set up to evaluate 2. Turn on V of the circuit by inserting the shunt in OUT the performance of the LTC3649. For proper measurement header JP2 (RUN) into the ON position. The output equipment configuration, set up the circuit according to voltage should be regulating. Measure V it should OUT the diagram in Figure 1. Before proceeding to test, insert measure 5.0V 2% (Do not apply more than the rated shunt into JP2 (RUN) into OFF position, which connects maximum voltage of 60V to the board or the part may the RUN pin to ground (GND), and thus, shut down the be damaged). Vary the V load, which should not OUT output. Set jumper JP1 (MODE) into FCC (forced counties exceed 4A. Vary the input voltage from 6V 55V, the conduction mode) position. Set jumper JP3 (V ) into V it should measure 5.0V 2%. OUT OUT 5.0V position. 3. Set JP2 (RUN) into OFF and then jumper JP3 (V ) OUT NOTE: When measuring the input or output voltage ripple, into 3.3V position. care must be taken to avoid a long ground lead on the 4. Turn on V of the circuit by inserting the shunt in OUT2 oscilloscope probe. Measure the input or output voltage header JP2 (RUN) into the ON position. The output ripple by touching the probe tip directly across the V or IN voltage should be regulating. Measure V it should OUT V and GND terminals. See Figure 2 for proper scope OUT measure 3.3V 2% (Do not apply more than the rated probe technique. maximum voltage of 60V to the board or the part may 1. With the DC2113A set up according to the proper be damaged). Vary the V load, which should not OUT measurement and equipment in Figure 1, apply 12V at exceed 4A. Vary the input voltage from 16V 55V, the V . Measure V it should read 0V. If desired, one V it should measure 3.3V 2% IN OUT OUT can measure the shutdown supply current at this point. 5. Set output current to zero and move jumper JP1 (MODE) The supply current will be approximately 14A, or less, into BURST position and measure V for 3.3V. OUT in shutdown. 6. Set output current to zero and move jumper JP1 (MODE) into BURST position and measure V for 5.0V. OUT + SUPPLY + + LOAD + + + Figure 1. Proper Measurement Equipment Setup dc2113afb 2