Today's field programmable gate arrays (FPGAs) and microcontrollers with internal analog-to-digital converters (ADCs) are capable of low-resolution and low-voltage analog inputs. However, they fall short on being able to meet the needs of industrial control and industrial automation applications, where isolation, higher resolutions, and higher voltage system solutions are often needed. The Santa Fe (MAXREFDES5#) subsystem reference design is a 16-bit high-accuracy industrial analog front end (AFE) that accepts -10V to +10V, 0 to 10V, and 4–20mA current loop signals with isolated power and data integrated into a small form factor. The Santa Fe design integrates low-noise high-impedance analog buffers (MAX9632); a highly accurate ADC with innovative on-chip attenuation (MAX1301); an ultra-high precision 4.096V voltage reference (MAX6126); 600VRMS data isolation (MAX14850); and isolated/regulated +12V, -12V, and 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 Santa Fe subsystem design block diagram.