Demonstration circuit 2822A features the LT8618, a high efficiency 65V, 100mA synchronous step-down regulator. The DC2822A demo board is designed for 100mA at 5V output from a 5.5V to 60V input with switching frequency of 2MHz. The wide input range allows a variety of input sources, such as automotive batteries and industrial supplies. The LT8618 is a high efficiency, and high frequency synchronous monolithic step-down switching regulator in a 3mm × 2mm DFN package with exposed pads for low thermal resistance. The regulator’s ultralow 2.5μA quiescent current with the output in full regulation enables applications requiring highest efficiency at very light load currents, such as automotive and battery powered portable instruments.
Peak current mode control with minimum on-time of as small as 35ns allows high step-down conversion even at high frequency. The LT8618 switching frequency can be programmed via an oscillator resistor over a 200kHz to 2.2MHz range. The default frequency of the DC2822A is 2MHz.
The DC2822A demo board has an EMI filter installed. The EMI performance of the board is shown on Figure 2. The red line in radiated EMI performance is CISPR25 Class 5 peak limit. The figure shows that the circuit passes the test with a wide margin.
The LT8618 data sheet gives a complete description of the part, operation and application information. The data sheet must be read in conjunction with this demo manual. The layout recommendations for best thermal performance are available in the data sheet Application Information section. Contact ADI applications engineer for technical support.