High-efficiency synchronous 42V, 6A step-down regulator integrates current sensing

Linear Technology has unveiled the LT8613, a new 6A, 42V input capable synchronous step-down switching regulator with integrated current sensing. Synchronous rectification delivers efficiency as high as 95% while Burst Mode operation keeps quiescent current under 3µA in no-load standby conditions. Its 3.4V to 42V input voltage range makes it ideal for automotive and industrial applications. Its internal high efficiency switches deliver up to 6A of continuous output current to voltages as low as 0.97V. An internal current sense amplifier with monitor and control pins enable accurate input or output current regulation and limiting. The LT8613’s Burst Mode operation offers ultralow quiescent current, making it well suited for applications such as automotive 'always-on' systems, which need to extend operating battery life. The LT8613’s unique design maintains a minimum dropout voltage of only 250mV at 3A under all conditions, enabling it to excel in scenarios such as automotive cold-crank. Furthermore, a fast minimum on-time of only 40ns enables 2MHz constant frequency switching from a 16V input to a 1.5V output, enabling designers to optimize efficiency while avoiding critical noise-sensitive frequency bands. The LT8613’s 28-lead 3mm x 6mm QFN package and high switching frequency keeps external inductors and capacitors small, providing a compact, thermally efficient footprint. The LT8613 utilizes internal top and bottom high efficiency power switches with the necessary boost diode, oscillator, control and logic circuitry integrated into a single die. Low ripple Burst Mode operation maintains high efficiency at low output currents while keeping output ripple below 10mVP-P. Special design techniques and a new high speed process enable high efficiency over a wide input voltage range, and the LT8613’s current-mode topology enables fast transient response and excellent loop stability. Other features include internal compensation, a power good flag, output soft start/tracking and thermal protection. The LT8613EUDE is packaged in a 3mm x 6mm QFN package. An industrial temperature version, the LT8613IUDE, is tested and 'guaranteed' to operate from a -40C to 125C junction temperature, says the company.