Stacked-Inductor Package Enhances Cooling of 40A Regulators

Linear Technology Corporation introduces the LTM4636, a 40A step-down µModule® switching regulator with 3D construction for quicker heat dissipation and cooler operation in a small package. 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 degrees C rise over ambient temperature. Full-power 40W is delivered up to 83 degrees C ambient and half-power 20W is supported at 110 degrees 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 degrees C rise and 88% efficiency (12Vin, 1Vout, 400LFM). Up to 6 devices in parallel can deliver up to 240A of Current.

Device 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 LTM4636 µModule 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 LTM4636 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 to 125 degrees C. 1,000-piece price starts at $38.85 each.