Demonstration Circuit DC2874A shows the LTC3310S 10A, Low Voltage, Synchronous Step-Down Silent Switcher operating as a multiphase 2.0MHz 3.3V to 1.2V buck regulator. The DC2874A has three build options to provide a two phase 20A, three phase 30A, or four phase 40A output solution. The LTC3310S supports adjustable output voltages from 0.5V to VIN and operating frequencies from 500kHz up to 2.25MHz in multiphase operation.
DC2874A operates in pulse skip mode and allows the slave phases to stop switching first before the master starts skipping pulses for better low current efficiency.
The DC2874A 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 illustrate the CISPR25 Class 5 peak limits for the conducted and radiated emission tests.
The Efficiency vs. Load graph shows the efficiency of the circuit with a 3.3V input for the 2-, 3-, 4-phase circuits.
The LTC3310S datasheet gives a complete description of the device, operation and application information. The data sheet must be read in conjunction with this demo manual. The LTC3310S is assembled in a 3mm x 3mm LQFN package with exposed pads for low thermal resistance.