When looking at the RN73R series of chip resistors from KOA Speer Electronics, Inc. such as part number RN73R2ATTD4701B25 (2019-RN73R2ATTD4701B25TR-ND), you may notice that two different power ratings are listed. The description lists it as 1/8W and the detailed description and product attributes list it as 1/4W, which leads many to believe that our website has an error. However, when you look at the datasheet you will also find both wattages listed for our example part number RN73R2ATTD4701B25(seen below).
So how do you know which version of a part you have? We contacted the manufacturer to get to the bottom of this.
The answer is you have both. Here is what KOA Speer Electronics had to say on the matter:
"The lower rating is the ‘standard’ rating. You can use the part at the higher power rating, as long as the terminal temperature is kept below the rated terminal temperature that is listed.
The part is exactly the same, but the customer may need to use a larger pad on the board or some other method to help dissipate the heat (to keep the terminal temperature low) to allow the part to be used at the higher power rating."