Based on the phase-coexistence transport model, an expression for the temperature coefficient of resistivity (TCR) behavior in doped manganites is proposed. The derived maximum TCR value (TCRmax), being related to polaron binding energy, transition temperature, and disorder in doped manganites, describes the observed “universal law” that the TCRmax is decreased, when TC increases. The calculated results are strongly supported by experiments and are analyzed within the framework of a microscopic transport mechanism. Correlation of the proposed TCR behavior to the transport parameters creates an opportunity to improve the TCRmax value in doped manganites, for uncooled bolometric applications.