Criteria of Low-Noise Thick-Film Resistors

Abstract

Our simple model of the noise of a thick-film resistor leads to two limiting cases. For thick-film resistors with a conduction dominated by the glass interface, the relative noise is proportional to the sheet resistance, R. For thick film resistors, where the conduction is mainly dominated by the current constrictions in the contact areas between grains, the relative noise is proportional to R3. Both trends have been observed. Some criteria of low-noise thick-film resistors are derived from the developed noise relations. The major conclusion is that measurements of the noise index are a nondestructive way to check quantitatively the operations used to manufacture high-quality thick-film resistors. Inadequate materials or treatments, weak or brittle wire bonds and reliability are easily detected by 1/f noise measurements. © 1977, Gordon and Breach Science Publishers Ltd.