Power_electronics Features

NewSpace demands low voltage, high current power for performance and longevity - Nov 2022
Matt Renola, Senior Director, Global Business Development – Aerospace & Defense
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Power Electronics Europe News
Synchronous step-down regulator reduces EMI/EMC emissions

It delivers 93% efficiency at 2MHz and low EMI/EMC emissions due to well controlled switching edges, its internal construction with an integral ground plane and the use of copper pillars in lieu of bond wires, says the company.


Its Silent Switcher 2 architecture uses two internal input capacitors as well as internal BST and INTVCC capacitors to minimise the area of the hot loops. The improved EMI/EMC performance is not sensitive to board layout, says the company, simplifying design and reducing risk even when using two-layer PC boards. The regulator passes the automotive CISPR 25, Class 5 peak EMI limits with a 2MHz switching frequency over its entire load range. Spread spectrum frequency modulation is available to lower EMI/EMC levels further.


The 3.0 to 42V input voltage range is suitable for automotive and industrial applications. The internal high efficiency switches deliver up to 2.0A of continuous output current and peak loads of 3.0A to voltages as low as 0.774V. The Burst Mode operation offers only 2.5µA of quiescent current, suitable for automotive always-on systems, to extend operating battery life. The regulator’s design maintains a minimum dropout voltage of only 400mV (at 1.5A) under all conditions, for use in automotive cold crank.  A minimum on-time of only 45ns enables 2.0MHz constant frequency, switching from a 16V input to a 1.5V output, to optimise efficiency while avoiding critical noise-sensitive frequency bands.


The 16-lead, 3.0 x 3.0mm LQFN package and high switching frequency are claimed to keep the external inductor and capacitors small, for a compact, thermally efficient footprint.


Internal top and bottom high efficiency power switches are included, 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. The switching frequency is programmable and synchronisable from 200kHz to 2.2MHz.


The current mode topology enables fast transient response and loop stability, complemented by other features such as internal compensation, a power-good flag, output soft-start/tracking and thermal protection.


An industrial temperature version (LT8609SIV) operates from -40 to 125°C.




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