Demonstration Circuit DC3251A features the LTC3302A, 5 V, 2 A synchronous step-down silent switcher operating as a 2 MHz, 3.3 V to 1.2 V, 2 A buck regulator. The LTC3302A supports adjustable output voltages from 0.5 V to VIN. The LTC3302A is a compact, high efficiency, and high-speed synchronous monolithic step-down switching regulator. A minimum on-time of 27 ns enables high VIN to low VOUT conversion.
The DC3251A operating mode can be selected as Burst Mode operation, skip (PS) or forced continuous (FC) mode. Setting JP1 to the SKIP position allows the LTC3302A to sync to a clock frequency from 1.6 MHz to 2.4 MHz. The LTC3302A operates in forced continuous mode when syncing to an external clock.
The DC3251A also has an EMI filter to reduce conducted EMI. This EMI filter can be included by applying the input voltage at the VIN EMI terminal. The EMI performance of the board is shown in the EMI Test Results section. The red lines in the EMI performance graphs show the CISPR25 Class 5 peak limits for the conducted and radiated emission tests.
The LTC3302A data sheet gives a complete description of the device, operation, and application information. Full specifications on the LTC3302A are available in the LTC3302A data sheet available from Analog Devices, Inc., and must be consulted with the user guide when using the DC3251A evaluation board. The LTC3302A is assembled in a 2 mm × 2 mm FCQFN package with side wettable flanks (SWF) for visual solder inspection. The layout recommendations for low EMI operation and maximum thermal performance are available in the data sheet section Low EMI PCB Layout.
