SBOS946 September 2020 INA848
PRODUCTION DATA
From Figure 9-6, the source resistance is shown to be one main contributor. Figure 9-8 plots all the individual noise contributors depending on the source resistance. The reference voltage noise is neglegible.
If the source resistance is below 20 Ω, the voltage noise of the INA (typically 1.3 nV/√Hz) is dominating. If the source resistance is increasing (> 20 Ω) the thermal noise of the source resistance is dominating. At this point the low-noise advantage of the INA848 does not provide additional value. In applications with even higher source resistance (> 1 kΩ), the current noise of the INA starts to dominate, and thus, should be optimized.