SLASFM1A June 2025 – December 2025 AFE10004-EP
PRODUCTION DATA
Remote junction temperature sensors are typically implemented in a noisy environment. Noise is most often created by fast digital signals that can corrupt measurements. The device has a built-in, 65kHz filter on the D+ and D– inputs to minimize the effects of noise. However, to make the application more robust against unwanted coupled signals, place a bypass capacitor differentially across the inputs of the remote temperature sensor. For this capacitor, select a value between 100pF differential and 1nF. Some applications attain better overall accuracy with additional series resistance; however, this increased accuracy is application specific. When series resistance is added, do not let the total value exceed 1kΩ. If filtering is required, suggested component values are 100pF differential and 50Ω on each input; exact values are application specific.
Additionally, a digital filter is available for the remote temperature measurements to further reduce the effect of noise. This filter is programmable and has two levels when enabled. Level 1 performs a moving average of four consecutive samples. Level 2 performs a moving average of eight consecutive samples. The value stored in the remote temperature result register is the output of the digital filter, and is the value being monitored for alarm conditions. The digital filter provides additional immunity to noise and spikes on the thermal alarm outputs. To enable or disable the filter, program the desired levels in the digital filter register. Figure 6-5 and Figure 6-6 show the filter response to impulse and step inputs. The digital filter is disabled by default.