The XTR105 is typically used with an external transistor (Q₁) to regulate the power dissipation of the 4-20mA loop. This allows the resulting localized self-heating to be distanced from the precision circuitry of the XTR105 and reduces over-temperature drift errors.

The XTR105 can be used without the Q₁ transistor if the application requirements do not lead to violation of the device Absolute Maximum Requirements, such as the maximum junction temperature. Calculate the peak power dissipation and multiply by thermal resistance to determine the associated junction temperature rise. Minimize overheat conditions for reliable long-term operation.

Place supply bypass capacitors close to the package and make connections with low-impedance conductors. Reduce trace lengths for R_G to minimize coupled environmental noise. If the loop power supply is electrically noisy, implement filtering using decoupling capacitors and small resistors or dampening inductors in series with V+.