2-3A, 42-Vin Silent Switcher offers low-EMI regulation
The architecture uses two internal input capacitors as well as internal BST and INTVCC capacitors to minimize the area of the ‘hot loops’. The LT8609S design reduces EMI/EMC emissions due to very well controlled switching edges, its internal construction with an integral ground plane and the use of copper pillars in lieu of bond wires. This improved EMI/EMC performance is not sensitive to board layout, simplifying design and reducing risk even when using two-layer PC boards. The LT8609S easily pass the automotive CISPR 25, Class 5 peak EMI limits with a 2 MHz switching frequency over its entire load range. Spread spectrum frequency modulation is available to lower EMI/EMC levels further.
The LT8609S’s synchronous rectification delivers efficiency as high as 93% with a switching frequency of 2 MHz. Its 3.0V to 42V input voltage range is suitable for automotive and industrial applications. The internal high efficiency switches deliver up to 2A of continuous output current and peak loads of 3A to voltages as low as 0.774V. The LT8609S’s Burst Mode operation offers 2.5 µA of quiescent current, for applications such as automotive always-on systems, needed to extend operating battery life. The LT8609S’s unique design maintains a minimum dropout voltage of 400 mV (at 1.5A) under all conditions, for scenarios such as automotive cold crank. A fast minimum on-time of only 45 nsec enables 2 MHz constant frequency, switching from a 16V input to a 1.5V output, optimizing efficiency while avoiding critical noise-sensitive frequency bands. The LT8609S’s 16-lead, 3 x 3 mm LQFN package and high switching frequency, which keeps the external inductor and capacitors small, providing a compact, thermally efficient footprint.
The LT8609S 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 10 mVP-P. Its switching frequency is programmable and synchronizable from 200 kHz to 2.2 MHz. Its 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.
LT8609S.
Pricing starts at $2.75 (1,000).
Analog Devices/Linear Technology; www.linear.com/product/LT8609S
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