Lighting applications

Product portfolio for lighting

Package options for lighting

Good efficiency, ease-of-use and EMI performance at an attractive cost position make the CoolMOS™ CE series the product of choice for LED drivers or LED tubes in buck, flyback, PFC and LLC topology. Its benefits include an improvement in efficiency and thermal behavior compared to standard MOSFETs.

CoolMOS™ products aimed at lighting bring the benefits of highest quality and delivery reliability as outlined in the overview section for the CoolMOS™ portfolio. However, the CoolMOS™ CE series has been defined with a particular focus on the customers’ needs, for an attractive price and fastest supply availability: at any given time and for any product of the CoolMOS™ CE series, orders of up to 30k units can be shipped from our distribution center within 5 days.

With the rapid conversion from CFL to LED lighting, customer requirements are rapidly changing: on the one hand, power levels are further decreasing, while on the other hand, increasing cost pressure compels power designers to optimize designs to a fraction of a cent. The completion of the CoolMOS™ CE portfolio with the SOT-223 package is Infineon’s answer to this challenge: it facilitates a further reduction in BOM cost – and additional footprint optimization in some designs – with only a minor compromise in terms of thermal behavior.

SOT-223 as drop-in replacement for DPAK at a lower cost

The SOT-223 package with a decapped middle pin is fully compatible with the footprint of a DPAK, therefore allowing one-on-one drop-in replacements and second sourcing.

The thermal behavior of the SOT-223 primarily depends on the layout of the board where the package is used and on the power consumed. We have measured the thermals in a test environment and compared them with a simulation. Compared to a DPAK positioned on a typical DPAK footprint, the SOT-223 displays the following thermal behavior.

Same footprint as DPAK – when mounted on a standard DPAK footprint, the SOT-223 package shows a temperature elevated by 4–5K. This behavior makes the SOT-223 suitable for designs with a thermal margin

Footprint of DPAK plus ~20mm² additional copper area – in many designs, the MOSFET is mounted on a larger Cu area which serves as a heatsink embedded in the PCB. As soon as 20mm2 Cu or more is available in addition to the DPAK footprint, the temperature increase is no more than 2–3K above DPAK and the SOT-223 can be used as a drop-in replacement

SOT-223 on SOT-223 footprint – when mounted on the SOT-223 footprint without an additional surrounding Cu area, the package leads to a 10°C temperature increase compared to a DPAK. This means that the option of space savings via the SOT-223 is only useful for very low power applications

The laboratory findings on thermal behavior are confirmed by a thermal simulation with T_ambient = 70°C and P_loss = 250mW. The size of the copper area in the footprint is shown on the x-axis, while the y-axis displays the temperature of the package top side. In the case of an SOT-223 on DPAK footprint, the 4–5K temperature increase over DPAK is confirmed. But when used in conjunction with an enlarged copper area of ~20mm², a temperature increase of 2–3K is measured.