The LT3579 incorporates two integrated 42 V switches, a 3.4 A master switch and a 2.6 A slave switch, which can be tied together for a total current of 6 A. The LT3579 operates from an input voltage range of 2.5 V to 16 V, with transient protection to 40 V, making it suitable for applications with input sources ranging from a single-cell Li-Ion to automotive inputs. The LT3579 is ideal for many local power supply designs as it can be configured as either a boost, SEPIC or an inverting converter. The device's 4 mm x 5 mm QFN package (or TSSOP-20E) and tiny externals ensure a compact footprint while minimizing solution cost.

The LT3579's low VCESAT switches, 0.25 V (tied together at 5.5 A), deliver efficiencies up to 90 percent. With both switches combined from a 5 V input, the LT3579 can deliver up to 1.7 A at 12 V or 1.2 A at -12 V. For high voltage outputs, the LT3579's slave switch enables high power charge pump topologies which are efficient and require few external components. The LT3579's switching frequency can be programmed via a single resistor or synchronized to an external clock between 200 kHz and 2.5 MHz, minimizing external component sizes and avoiding “noise critical” frequency bands. Undervoltage lockout (UVLO) is user adjustable for optimal system performance. A single feedback resistor sets the output voltage, minimizing external components. Other features include external synchronization capability and junction temperature monitoring.

For applications requiring higher output current, the LT3579-1 offers a CLKOUT pin signal that is 180 degrees C out of phase with the internal oscillator, enabling the device to be used in multiphase applications.

Availability and Pricing

The LT3579EUF and LT3579-1EUF are available in 4 mm x 5 mm QFN-20 packages, priced starting at 3.30 US Dollars each for 1,000 piece quantities. The LT3579EFE and LT3579-1EFE are also available in a thermally enhanced TSSOP-20 packages, priced starting at 3.45 US Dollars each for 1,000 piece quantities. Industrial temperature (-40 to 125 degrees C) versions, the LT3579IUFD, LT3579-1IUFD and the LT3579IFE, LT3579-1IFE are also available from stock. Pricing starts at 3.67 US Dollars and 3.83 US Dollars each, respectively for 1,000 piece quantities.

Datasheet: LT3579