Synchronous Step-Down Switcher Delivers 94% Efficiency at 2MHz

The LT8645S 8A, 65V-input synchronous step-down switching regulator features a unique Silent Switcher 2 architecture that uses two internal input capacitors and BST and INTVCC capacitors to minimize the area of the hot loops. Combined with very well controlled switching edges and internal construction with an integral ground plane and the use of copper pillars in lieu of bond wires, the LT8645S dramatically reduces EMI/EMC emissions. This improved EMI/EMC performance is not sensitive to board layout, simplifying design and reducing risk even when using two layer PC boards. The LT8645S can pass the automotive CISPR25, Class 5 peak EMI limits with a 2MHz switching frequency over its entire load range. Spread spectrum frequency modulation is also available to lower EMI/EMC levels further.


The LT8645SEV is packaged in a 4 mm x 6 mm LQFN package. An industrial temperature version, the LT8645SIV, operates from a –40°C to +125°C. Pricing starts at $5.95 each/1,000. For more information and a datasheet, visit