Dual input, lossless PowerPath control

Linear Technology Korea (CEO Hong Sa-kwak) announced the launch of the LTC3126, a 2.5A, 42V synchronous step-down switching regulator with integrated dual-input PowerPath™ control.

A unique power stage topology allows operation from either of two independent power sources, with seamless internal switching between the two inputs to maintain a stable output voltage even during hot-plug and power-off events.

This device also combines internal power switches and synchronous rectification to deliver 95% efficiency over a wide input voltage range, while switching at 2MHz, providing fast transient response and excellent loop stability. These features allow designers to avoid critical noise-sensitive frequency bands, such as AM radio, while still providing a very compact solution footprint.

The LTC3126's current-mode topology is internally compensated, eliminating the need for external compensation components. Burst Mode® operation maintains high efficiency at low output currents while keeping peak-to-peak output ripple below 1%. Furthermore, its no-load standby current draw of less than 2µA makes it ideal for always-on systems and portable applications.

The LTC3126's wide input (2.4V to 42V) and output voltage (0.818V to VIN) ranges make it well suited for automotive applications that require stable output during cold-crank, load dump, and stop-start scenarios. Other key applications include portable industrial/telecommunications test equipment, battery and supercapacitor backup power systems, automotive power with battery backup, UPS, and systems powered by unstable adapter power or conventional single- or multi-cell battery stacks.

The LTC3126's integrated lossless PowerPath circuitry supports seamless operation from two separate input power supplies. Priority input modes with pin-selectable ideal diode-OR and user-programmable undervoltage lockout (UVLO) thresholds provide complete control when switching between input power supplies.

This fast automatic switchover enabled by internal PowerPath eliminates the need for holdup capacitors and minimizes output voltage fluctuations. Active input channel indicators and individual input/output power good signals provide complete feedback on the power system's status. Other features include a 1µA shutdown current draw, internal soft-start, and thermal enhancements.

The LTC3126 is available in thermally enhanced 28-lead TSSOP and 4mm x 5mm QFN packages. Because the LTC3126's high switching frequency allows it to be used with small external inductors and capacitors, these packages provide a compact, thermally efficient footprint. Both E- and I-grade devices have an operating temperature range of –40°C to 125°C. A high-reliability version, the H-grade, is available only in TSSOP and is tested and specified from –40°C to 150°C. Pricing starts at $6.25 each in 1,000-piece quantities.