In industrial control and industrial automation applications, high-resolution data converters are often required. Although today's field programmable gate arrays (FPGAs) and microcontrollers may integrate analog-to-digital converters (ADCs), in many cases, the resolution is not high enough and isolation is lacking. The Campbell (MAXREFDES4#) subsystem reference design is a 16-bit high-accuracy industrial analog front end (AFE) that accepts a 4–20mA current loop or a 0.2V to 4.096V voltage input signal, and features isolated power and data—all integrated into a small form factor. The Campbell design integrates a precision low-noise buffer (MAX44250), a high-accuracy ADC (MAX11100), an ultra-high-precision 4.096V voltage reference (MAX6126), 600VRMS data isolation (MAX14850), and isolated/regulated 5V power rails (MAX256/MAX1659). This AFE solution can be used in any application that needs high-accuracy analog-to-digital conversion, but it is mainly targeted for industrial sensors, industrial automation, process control, programmable logic controllers (PLCs), and medical applications.
Figure 1. The Campbell subsystem design block diagram.