The design helps collect analog data with a 16-bit ADC, useful for industrial automation, medical devices, and process control, making development easier.
High-resolution data converters are essential in industrial control and automation. While modern FPGAs and microcontrollers include ADCs, their resolution is often insufficient, and they may lack isolation. The Campbell (MAXREFDES4) subsystem reference design from Analog Devices (ADI) provides a 16-bit high-accuracy industrial analog front end (AFE) that supports a 4–20mA current loop or a 0.2V to 4.096V voltage input. It includes isolated power and data in a compact form. Key components include a low-noise buffer, a high-accuracy ADC, a 4.096V voltage reference, 600VRMS data isolation, and isolated 5V power rails.
This reference design is useful for embedded system developers integrating high-resolution ADCs with FPGAs or microcontrollers; medical device designers needing isolated analog front ends for patient monitoring and diagnostics; power and signal integrity engineers working with isolated power and data transmission; and researchers exploring precision measurement solutions. By providing a ready-to-use isolated analog front end, this design helps improve accuracy, reduce complexity, and accelerate development.
The reference design is suitable for high-accuracy, isolated analog signal acquisition in various applications, including industrial sensors for monitoring pressure, temperature, and flow; automation and process control in manufacturing and robotics; and programmable logic controllers (PLCs) for factory automation. It also supports medical equipment such as patient monitoring systems, test and measurement instruments, and energy and power systems for smart grids and industrial power management.
The Pmod specification supports 3.3V and 5V modules with different pin assignments. This module operates only at 3.3V and follows the SPI pin assignments shown on the right. The Campbell subsystem is designed for a high-accuracy 4–20mA current loop or a 0.2V to 4.096V input voltage analog-to-digital data acquisition system. It includes isolated power and isolated data.
The MAX44250 op amp buffers a 4–20mA current-loop sense voltage on a 200Ω load resistor or a 0.2V to 4.096V voltage signal. The MAX11100 is a 16-bit SAR ADC with AutoShutdown and a 1.1µs wake-up time. Its reference input is driven by the MAX6126, a 4.096V voltage reference with 0.02% initial accuracy and a 3ppm/°C maximum temperature coefficient.
The MAX256 provides isolated power by converting 3.3V to 12V using a TGM-H281NF Halo transformer with a 1:2.6 turns ratio and an on-board voltage doubler. The MAX14850 ensures data isolation, with a combined power and data isolation of 600VRMS.
This reference design helps engineers implement precise, isolated analog data acquisition in industrial environments while simplifying development and integration.
ADI has tested this reference design. It comes with a bill of materials (BOM), schematics, assembly drawing, printed circuit board (PCB) layout, and more. The company’s website has additional data about the reference design. To read more about this reference design, click here.
