KOA wide terminal chip resistors, including the WK73R, WK73S, WG73, and WU73 series, have the terminals on the long sides of the package instead of the short sides. Because so much heat in surface mount resistors is drawn off through the terminals, these longer metal terminals act as heatsinks, and at a given power the temperature of the resistor is lower than it would be for a traditional package. That allows KOA to increase the power available in a given substrate, and it allows you to get more power density into a smaller space.

Another major advantage is the separation between the terminals is smaller. Chip resistors are based on ceramic, in applications that go up and down in ambient temperature, the difference in thermal expansion and contraction between the ceramic part and the circuit board will cause stress in the solder joints, eventually leading to cracking. Which is why wide-terminal parts can be used for many more thermal cycles than standard chip resistors.

KOA Speer engineering video explains how pulse power can affect surface mount resistors and how to select the proper resistor for your application. If the application has high power pulses an untrimmed resistor offers more element to carry the current and a greater amount of material to spread the heating out across, but compromises the tolerance band available, typically within 10% of the desired resistance value. Another option is a resistive element that is patterned to be longer, and thus can use a lower-resistivity but higher-stability material, resulting in a resistor that can withstand higher temperatures without damage. KOA''s SG73P series not only has up to five times the pulse power rating of a standard surface mount resistor, it also has a higher continuous power rating for its size.

For applications with widely varying resistance values or the possibility of high electrostatic discharge, a thin film resistor is ideal. For other applications where you need a single resistor to remain stable at high power or high temperature, a thick film resistor will work. It won''t be quite as stable, but it can handle power and pulses better and is made from a ceramic and glass element instead of a metal one, so it has no issues with high humidity applications. With thin film resistors in high demand/short supply, learn how thick film resistors can be a good alternative for high stability applications.