Synchronous step-down regulators offer 96% efficiency

December 18, 2013 // By Peter Clarke
Linear Technology Corp. has introduced the LT8610A and LT8610AB synchronous step-down switching regulators that operate from 3.5A, 42V supplies

Synchronous rectification delivers efficiency as high as 96 percent while Burst Mode operation keeps quiescent current under 2.5-microamps in no-load standby conditions. Their 3.4V to 42V input voltage range makes them suitable for automotive and industrial applications.

The internal 5A switches can deliver up to 3.5A of continuous output current to voltages as low as 0.97V. The LT8610A/AB's design maintains a minimum dropout voltage of only 200mV at 1A under all conditions. Furthermore, a fast minimum on-time of only 30ns enables 2MHz constant frequency switching from a 16V input to a 1.0V output, so designers can optimize efficiency while avoiding critical noise-sensitive frequency bands. The LT8610A/AB’s 16-lead thermally enhanced MSOP package and high switching frequency keeps external inductors and capacitors small, providing a compact thermally efficient footprint. The LT8610AB offers higher efficiency at very light loads of less than 0.5mA when compared to the LT8610A, but this does result in slightly higher output ripple.

The LT8610A and LT8610AB share all of the performance and features of the LT8610 with the following improvements. First, they deliver 3.5A of continuous output current, in lieu of the LT8610’s 2.5A capability. Secondly, their minimum on-time has been reduced from 50ns to 30ns, enabling 16V to 1V step-down conversion at 2MHz, compared to 1.8V for the standard LT8610. All other electrical parameters are identical to the standard LT8610.

The LT8610AEMSE and LT8610ABEMSE are packaged in thermally enhanced MSOP-16 packages and are priced starting at $3.75 each. An industrial temperature version, the LT8610AIMSE and LT8610ABIMSE are tested and guaranteed to operate from a -40°C to 125°C operating junction temperature and are priced starting at $4.13 each. Automotive temperature versions, the LT8610AHMSE and LT8610ABHMSE are tested and guaranteed to operate from a -40°C to 150°C operating junction temperature and are priced starting at $4.38 each. All pricing is for 1,000- piece quantities and all versions are available from stock.

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