SBOS344D September 2005 – November 2023 XTR117
PRODUCTION DATA
Refer to the PDF data sheet for device specific package drawings
The 4-20 mA control-loop stability must be evaluated for any XTR117 design. A 10‑nF decoupling capacitor between V+ and IO is recommended for most applications. As this capacitance appears in parallel with the load resistance RLOAD from a stability perspective, the capacitor and resistor form a filter corner that can limit the bandwidth of the system. Therefore, for HART applications, use a bypass capacitance of 2 nF to 3 nF instead.
For applications with EMI and EMC concerns, use a bypass capacitor with sufficiently low ESR to decouple any ripple voltage from the VLOOP supply. Otherwise, the ripple voltage couples onto the 4‑mA to 20‑mA current source, and appears as noise across RLOAD after the current-to-voltage conversion.