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Adler's Linear Technology Introduces 8A, 65V Input Synchronous Step-Down Switching Regulator LT8645S

Friday, August 17, 2018

Linear Technology Corporation, a subsidiary of Analog Devices, Inc. (ADI), introduced the LT8645S, an 8A, 65V input synchronous step-down switching regulator. Its unique Silent Switcher® 2 architecture uses two internal input capacitors and internal BST and INTVCC capacitors to minimize thermal loop area. Combining a very well-controlled switch edge with an internal construction with an integral ground plane and a copper post instead of a bond wire, the LT8645S is designed to significantly reduce EMI / EMC emissions.

This improved EMI / EMC performance is not susceptible to board layout, simplifying design and reducing risk, even when using two-layer PC boards. With a switching frequency of 2MHz over the entire load range, the LT8645S can easily meet the Class 5 peak EMI limits of automotive CISPR 25. The device also provides spread spectrum frequency modulation to further reduce EMI / EMC values.

The LT8645S's synchronous rectification delivers up to 94% efficiency at 2MHz switching frequency. Its 3.4V to 65V input voltage range is ideal for dual battery transport, 48V automotive and industrial applications. An internal high efficiency switch delivers up to 8A of continuous output current to voltages as low as 0.97V. The Burst Mode® operation of the LT8645S provides a quiescent current of only 2.5μA, making it ideal for applications such as always-on systems in automotive/transportation, as such applications require extended battery life.

The unique design of the LT8645S maintains a minimum dropout voltage of only 60mV (at 1A) under all conditions, allowing the device to perform well in automotive cold-start conditions. In addition, a fast 2M on-time of 40ns enables 2MHz constant frequency switching from 24V input to 2.0V output, allowing designers to optimize efficiency while avoiding critical noise-sensitive frequency bands. The LT8645S's 32-lead, 4mm x 6mm LQFN package and high switching frequency allow the use of small external inductors and capacitors, resulting in a compact footprint and high thermal efficiency solution.

The LT8645SEV is available in a 4mm x 6mm LQFN package. The industrial temperature grade version of the LT8645SIV is tested and guaranteed to operate over the –40°C to 125°C operating junction temperature range.

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Author:Brittany Antonia (The author of article owns the copyright.)