LTM4601 DC/DC ?Module thermal performance

The LTM4601 DC/DC ?Module is a complete high power density stepdown regulator for up to 12A continuous (14A peak) loads. The ?Module is housed in a 15mm x 15mm x 2.8mm LGA SMPs, thus the large power dissipation of the ?Module is a challenge in some applications. The purpose of this thermal application note is to provide guidelines for using the ?Module in ambient environments with or without air flow. Load current derating curves are provided for several input voltages and output voltages vs. ambient temperature and air flow. These derating curves provide guidelines for using the LTM4601 in ambient environments with regard to safe-operating-area (SOA). Also included are efficiency curves that are used to extrapolate the power loss curves used in this thermal application note. The approach is to measure the temperature of a design, derive thermal models for different cases and finally determine the junction-to-ambient thermal resistance in units of °C/W in the heat path. The data includes power loss curves, safe operating curves, thermal camera images and current derating curves vs. ambient temperature and air flow with and without a heat sink. 24V designs are analyzed for a worse case temperature rise due to the relatively lower efficiency exhibited in these higher input voltage designs.

View the PDF document for more information.