Linear Technology has developed a current mode, fixed frequency DC/DC converter with an internal 2A, 70V switch that has an ultralow quiescent current of only 7µA. This makes the converter suitable for always-on automotive or other industrial battery powered systems, writes Nick Flaherty.
The LT8494 starts up from an input voltage range of 2.5V to 32V and once running it operates from inputs from 1V to 60V, making it suitable for applications with input sources ranging from a single-cell Li-Ion to automotive inputs.
The LT8494 can be configured as a boost, single ended (SEPIC) or flyback converter. The switching frequency can be programmed via a single resistor between 250kHz and 1.5MHz, enabling designers to minimise external component sizes. The combination of a thermally enhanced TSSOP-20E or 4mm x 4mm QFN package and tiny externals ensures a very compact footprint while minimizing solution cost.
The LT8494’s internal, high efficiency 2A/70V switch delivers efficiencies of up to 83% while operating in a SEPIC configuration. A unique design using dual supply pins (VIN and BIAS) enables the device to operate from the most efficient supply, optimising efficiency over a wide range of conditions with an output ripple less than 10mV.
The LT8494 can operate with input supply voltages up to 60V for SEPIC topology and up to 32V, with ride through protection in boost and flyback topologies. Other features include a FMEA tolerant package (TSSOP-20E), power good indicator, programmable soft-start and thermal shutdown protection.
The LT8494 is available in a thermally enhanced TSSOP-20 package and industrial temperature (–40°C to 125°C) and high temperature (–40°C to 150°C) grades are also available.