LT8615

The evaluation board EVAL-LT8615-AZ is a 42V, 3.5A micropower synchronous step-down regulator with Silent Switcher^® powertrain featuring the LT^®8615.

The evaluation board is designed for a 5V output from a 5.5V to 42V input. The wide input range allows a variety of input sources, such as automotive batteries and industrial supplies. The LT8615 is a compact, high efficiency, high speed synchronous monolithic step-down switching regulator that consumes only 2.5μA of quiescent current when the output is regulated at 5V. Top and bottom power switches, compensation components, and other necessary circuits inside the LT8615 minimize external components and simplify design.

The SYNC pin on the evaluation board is grounded by default for low ripple burst mode operation. Moving JP1 to pulse skipping/sync position can change the operation mode to pulse skipping operation. To synchronize to an external clock, move JP1 to pulse skipping/sync and apply the external clock to the SYNC turret. Once JP1 is on the spread-spectrum position, V_CC is applied to the SYNC pin for low EMI spread spectrum operation. Figure 1on user guide shows the efficiency of the circuit.

The evaluation board has an EMI filter installed. Under spread-spectrum operation, the radiated and conducted EMI performances of the board (with EMI filter) are shown in Figure 2 and Figure 3 on user guide. The red lines in the figures are CISPR25 Class 5 peak limit. To use the EMI filter, the input should be tied to V_EMI, not V_IN. An inductor L2, which is a 0Ω jumper on the board by default now, can be added in the EMI filter to further reduce the conducted emission.

This board is suitable for a wide range of automotive, telecom, industrial, and other general-purpose applications. The LT8615 data sheet gives a complete description of the part, operation, and application information. Read the data sheet in conjunction with this user guide for the EVAL-LT8615-AZ.