4-20mA Current Loop Transmitter

The 4-20mA current loop is the dominant standard for sensor systems in many industries. This is because it is the simplest option to configure and connect. However, it also uses less wiring and connections than other signals, therefore reducing the overall system cost. In large locations, it is better for traveling long distances since the current doesn't degrade (unlike the voltage).

This design shows a possible transmitter solution with our precision digital power monitor (DPM), stable power source, and the low-power, analog-rich feature capabilities of our 16-bit RL78/I1D MCU.

System Benefits:

• The RL78/I1D is an analog and ultra-low power MCU for detector and sensor applications
• The ISL80410 is a high voltage, adjustable V_OUT, low quiescent current linear regulator suited for "always-on" applications
• Precision voltage from Renesas' ISL21080 Nanopower (310nA typical) voltage reference