Design Con 2015

SMT transformers boost power, shrink footprint

-May 15, 2014

Pulse Electronics’ ER25+ platform increases the throughput power of planar-core surface-mount transformers by 50%, compared to devices based on the ER28 platform, to deliver up to 800 W in a smaller 33.5×26.8×18.3-mm footprint. Engineers can use the PH9278NL transformers for isolation and voltage conversion in switched-mode power supplies aimed at data communication and intermediate bus converter applications.

The gain in power is achieved by increasing the effective cross-sectional area of the core by 40%. This results in lower core losses for a given number of winding turns. In addition, copper losses can be reduced by removing some winding turns. The flat coil windings have 50% lower direct current resistance compared to multilayer PCB technology, and the core design allows for a compact inter-connection and termination of the winding elements.

Transformer specifications include a frequency range of 200 kHz to 700 kHz, primary inductance of 37.8 µH minimum, and isolation of 1500 VDC. The devices operate over a temperature range of –40°C to +125°C.

PH9278NL planar transformers are RoHS-compliant and meet EIA481 requirements for tape-and-reel packaging. Prices range from $3.75 to $4.95 for lots of up to 50,000 units. Lead time is eight weeks.

PH9278NL transformer datasheet

Pulse Electronics,

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