DC1144A-A: 12V @ 300mA, 3 ~ 10V in, Boost

Demo circuits 1144A-A and 1144A-B feature the LT3580EDD in boost/inverting regulator configurations. The demo circuits demonstrate small size and low component count. The boost is designed to convert a 3-10V source to 12V at 300mA while the inverter converts a 5-12V source to -12V at 350mA. Both converters use only one feedback resistor to set the output voltage.

The LT3580 operates with inputs as high as 32V but in these demo boards the input is limited by the voltage rating of the input capacitors and the magnitude of the boost output. In a boost converter the input needs to be less than the output.

Care must be taken when operating the LT3580 at high input voltages as the junction temperature increases due to higher internal dissipation.

The LT3580 gets powered from the main input in both, DC1144A-A and DC1144A-B, but there is an option for a linear regulator built into the board that will allow the IC to be powered from a lower voltage. If this option is used, just cut the trace as shown in figure 6 and install the optional emitter follower regulator on the back of the board.

The LT3580 includes many other features such as synchronization to external clock, user configurable under voltage lockout, soft-start, frequency foldback, and it is easily configured as boost or inverting converter.

The circuits are intended for space-conscious applications such as local bias supplies, TFT-LCD bias supplies, GPS receivers, VFD bias supplies, and DSL modems.