Synchronous step-down switcher delivers high efficiency and ultralow EMI emissions

Analog Devices announces the Power by Linear LT8642S, a 10A, 18V input synchronous step-down switching regulator. Its Silent Switcher 2 construction uses two internal input capacitors as well as internal BST and INTVCC capacitors to reduce the area of the hot loops. The device dramatically decreases EMI emissions as a consequence of its controlled switching edges and its internal construction using copper pillars instead of bond wires and an integral ground plane. This enhanced EMI performance is not sensitive to PCB layout, making designs simpler and reducing risk even when using two-layer PC boards. The device easily passes the automotive CISPR 25, Class 5 peak EMI limits with a 2MHz switching frequency over its whole load range. Spread spectrum frequency modulation is available to lower EMI levels further. The device's synchronous rectification produces efficiency as high as 95% with a switching frequency of 2MHz. The device's 2.8V to 18V input voltage range is perfect for automotive and industrial applications. The internal high-efficiency switches produce up to 10A of continuous output current to voltages as low as 0.60V. The Burst Mode operation assures only 240µA of quiescent current. An external compensation pin allows fast transient response and current sharing for paralleling multiple devices. A fast minimum on-time of only 25ns allows 2MHz constant frequency switching from a 12V input to a 0.6V output. The device's 24-lead 4mm x 4mm LQFN package and high switching frequency keeps external inductors and capacitors small, offering a compact, thermally efficient footprint.