Demonstration circuit DC2907A features the LT8338, a low IQ, Synchronous Boost Converter in a thermally enhanced 10-lead plastic MSOP package. DC2907A is designed to convert a 4V to 16V source to 24V output, with up to 460mA of load current, depending on the input voltage. It was designed with a switching frequency of 2.2MHz.
DC2907A contains a selectable jumper, JP1, to aid in the selection of any of the five modes of operation. The default setting is Burst mode.
This converter features Spread Spectrum Frequency Modulation, SSFM. The input and output filters installed on the PCB help suppress EMI noise, but the use of SSFM makes it easier to pass CISPR25 class 5 conducted and radiated emissions testing for automotive vehicles. To perform an EMI evaluation for this converter include the input filter by connecting the input source to the VEMI terminal and select the Burst+SSFM JP1 setting.
EMI filters may not be necessary for all applications. For a lower parts count and BOM cost EMI filters can be removed. To do so, replace FB1 and FB2 with a zero ohm jumpers and remove all input and output filter components located inside the dashed-line rectangles on the schematic, plus C1 and C13.
Proper board layout is essential for maximum thermal performance. See the datasheet section “Thermal Considerations”.
The Performance Summary section details the ratings of the DC2907A at room temperature. The LT8338 datasheet gives a complete description of the part, operation and application information. The data sheet must be read in conjunction with this quick start guide for DC2907A.
The LT8338 is available in a thermally-enhanced 10 lead plastic MSOP package.