Analog Devices offers the DC2851A evaluation kit

     Evaluation Kit DC2851A is a four-channel synchronous step-down regulator with LT7200S. The LT7200S is ideal for high step-down ratio applications that require fast transient responses at high frequency operations due to its constant frequency, current mode architecture and phase-locked controlled punctuality.

     The input voltage range of the DC2851A is 2.9V to 18V, with each regulator capable of providing ±5A output current. Evaluation kits are designed for 1.2V, 1.8V, 3.3V and 5V outputs with switching frequency set to 1MHz. The DC2851A offers a different multi-channel combination based on the lt7200 to provide flexible output current ratings.

     The LT7200S features independent soft boot, output tracking and good power per output to simplify complex four-output converter designs. The output tracking and soft start pins allow control of the rise time and ramp rate of the output voltage. Each output can be independently disabled to low static current off mode via its own TRACK or RUN pins.

     The user option MODE/SYNC pins on the evaluation kit allow the component to operate in discontinuous mode to improve efficiency with light load current, or force continuous mode to operate to reduce output ripple at the expense of light load efficiency. The MODE/SYNC pin can also be used to synchronize the switching frequency to an external clock.

     The switching frequency of all regulators can be programmed in the 400kHz to 3MHz range via oscillator resistors or external clocks. At all frequencies, when the PHMODE pin is low, a 180° phase shift is maintained between channels 1 and 2, and between channels 3 and 4, reducing the input peak current and voltage ripple.

     The DC2851A has an EMI filter installed in the bottom layer. The conductive and radiant EMI performance of the plate is shown in Figure 4. The red line in Figure 4 is CISPR25 Class 5 peak limit. As can be seen from the figure, the circuit passed the test with a large margin. In order to achieve EMI/ EMC performance as shown in Figure 4, an input EMI filter is required and the input voltage should be applied to the VEMI turret.

     The LT7200S data sheet provides a complete description of the operation and application information of this part. Read the data table according to the DC2851A Quick Start Guide. The LT7200S is assembled in a 5mm x 6mm LQFN package with an exposed liner for low thermal resistance. Proper board layout is essential for both low EMI operation and optimal thermal performance.