What is the relationship between the noise level of metal foil resistors and temperature?

The relationship between the noise level of metal foil resistors and temperature is mainly reflected in their temperature coefficient (TCR) and thermoelectric potential effect. Here are a few key points:

1. Temperature coefficient (TCR): Metal foil resistors have an extremely low temperature coefficient, which means that even with temperature changes, the change in resistance value is very small. Specifically, within the temperature range of -55 ℃ to+125 ℃ and the reference temperature of+25 ℃, the Z-foil resistor has a typical TCR of ± 0.2 ppm/° C, while within the temperature range of 0 ℃ to 60 ℃ and the reference temperature of+25 ℃, the Z-foil resistor has a typical TCR of ± 0.05 ppm/° C. This low TCR enables the metal foil resistor to maintain a stable resistance value at different temperatures, thereby reducing noise.
2. Thermoelectric potential effect: The thermoelectric potential effect of metal foil resistors is relatively small, with a typical value of 0.05 μ V/℃. The thermoelectric effect refers to the electromotive force generated in resistive materials due to temperature gradients, which may affect the noise level of circuits. The low thermoelectric potential effect of metal foil resistors helps maintain lower noise levels at different temperatures.
3. Current noise: The current noise of metal foil resistors is very small, less than -40dB, and is 0.010 μ V (RMS)/Volt loading voltage. This means that even under temperature changes, metal foil resistors can maintain low noise levels, which is crucial for circuits that require low-noise applications.
In summary, the noise level of metal foil resistors is less affected by temperature, thanks to their low temperature coefficient and low thermoelectric potential effect. These characteristics enable metal foil resistors to provide stable low-noise performance over a wide temperature range.