Chip resistor frequency performance considerations for RF design

As frequencies increase the chip resistor capacitance, inductance and pad parasitics start playing a significant role in the performance of the resistor . Sometimes at higher frequencies a chip resistor may start behaving capacitive sometimes inductive. A Signal Processing Group Inc., high frequency product was to be designed using chip resistors of value 75 Ohm. We investigated the chip resistor frequency response and found that for the highest frequency response the 0201 size is the best. However, assembling 0201 is quite challenging. The next best choice is 0402. This too has its difficulties in assembly. Going further down is the 0603 size, which is easier to use but has poorer frequency response generally than the 0201 and 0402 sizes. However, in our case the resistor value was 75 Ohm. From looking at the characterizations done by a well known chip resistor vendor it appears that if the resistor value is below 100 Ohm, 0603 and 0402 both behave about the same. The conclusion: We can use 0603 which is easier to use. Please visit our website for more information and publications and descriptions of services.

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