Stacked-inductor packaging cools modules

Stacked-inductor packaging cools modules

New Products |
By Peter Clarke

By stacking its inductor on top of a 16mm x 16mm BGA package, the LTM4636 benefits from the exposed inductor as a heat sink, permitting direct contact with airflow from any direction to cool the device. The LTM4636 delivers 40W (12VIN, 1VOUT, 40A, 200LFM) with only 40°C rise over ambient temperature. Full-power 40W is delivered up to 83°C ambient and half-power 20W is supported at 110°C ambient.

The LTM4636 operates at 92%, 90% and 88% efficiency, delivering 15A, 30A and 40A, respectively, to a 1V load (12VIN). The µModule regulator is scalable, such that four LTM4636s in parallel current sharing mode deliver 160W with only 40°C rise and 88% efficiency (12VIN, 1VOUT, 400LFM).

The overall module height is 7.07mm, including the inductor stacked on top of a 16mm x 16mm x 1.91mm BGA package. In addition to dissipating heat from the top, the LTM4636 is designed to uniformly disperse heat from the bottom of the package to the PCB with 144 BGA solder balls, with banks of them assigned to GND, VIN and VOUT where high current flows. The regulator benefits system designers with its enhanced thermal performance in a small package resulting from the combination of impressive DC/DC conversion efficiency and enhanced heat dispersion.

The module operates from a 4.7V to 15V input supply and regulates an output voltage from 0.6V to 3.3V. Total DC output voltage accuracy is ±3% from –40°C to 125°C. 1,000-piece price starts at $38.85 each.

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