Compact resistors cut heat and power

An IRC Advanced Film Division product story

Edited by the Electronicstalk editorial team Feb 28, 2008

ULR resistors require much less board space than a comparably rated wirewound, making them suitable for voltage regulation modules, power supplies, DC/DC convertors and electric motor control devices

TT electronics IRC has released metal element chip resistors for high-volume, high-current power electronics applications.

They are designed to provide design engineers with an economical surface mount current sense device designed to maximise thermal performance and minimise power consumption.

The ULR series of resistors features tight TCRs and low inductance values.

According to Bryan Yarborough, Applications Engineer for IRC, the ULR series resistors are suitable for applications involving current detection and monitoring.

"The low inductance and TCR values, along with the higher power rating, allows power consumption in circuit designs to be minimised", said Yarborough.

"With a small footprint and surface mount design, the economical resistors require much less board space than a comparably rated wirewound, making them suitable for densely packed applications such as voltage regulation modules, power supplies, DC/DC convertors and electric motor control devices".

The ULR series resistors are available in 1206, 2010 and 2512 package sizes and feature power ratings of 1, 1.5, 2, 2.5 and 3W at 80C.

The resistance range is from 0.5 to 10mohm, with standard tolerances of +/-1% and +/-5% and TCRs as low as +/-50parts per million/C, depending on power rating and resistance value.

The operating temperature ranges from -55 to +170C.

IRC will also produce devices outside these specifications to meet customer requirements.

The ULR series resistors are available in two versions, indicated by a black or green protective coating.

Both types feature plated terminations that, in contrast to comparable components with copper terminals, streamline production and eliminate TCR degradation.

The black-coated resistors (1, 2W) are equipped with a low-resistance alloy plate.

The green-coated resistors (1, 1.5, 2, 2.5, 3W) feature a printed circuit board "clearance gap" in order to maximise thermal performance and keep the resistor's "hot spot" off the PC board.