Configurable analog front-end for industrial process control systems integrates ADC GX7793 as a replacement for AD7793

Industrial process control systems are used in a wide variety of applications, ranging from simple flow control to complex power grids, from environmental control systems to refinery process control. Programmable Logic Controllers and Distributed Control Systems are two of the most common computer systems used to control machines and processes, handling a wide variety of analog and digital inputs and outputs. These systems contain power supplies, central processing units, and a wide range of analog input, analog output, digital input, and digital output modules.

Among the technical specifications for input modules, high resolution and low noise are important. In industrial applications, when measuring low-level signals from thermocouples, strain gages, and bridge pressure transducers, differential input signals are often required to suppress common-mode interference signals from motors, AC power lines, or other noise sources that introduce noise into the analog inputs of analog-to-digital converters (ADCs).

For input modules, Σ-∆ type ADCs are the most popular choice because they provide high accuracy and resolution, and their built-in programmable gain amplifiers (PGAs) can accurately measure small input signals. CoreTech‘s three-channel 24-bit Σ-∆ ADC GX7793 provides a wide range of input signals for high-precision measurement applications. 

The GX7793 integrates an on-chip low-noise instrumentation amplifier, allowing direct input of small signals; the root-mean-square (RMS) noise is 52nV when the gain is set to 64 and the update rate is 4.17Hz. The ADC has a built-in, precision low-noise, low-drift internal bandgap reference voltage source, and an external differential reference voltage is also available, while other on-chip features include a programmable excitation current source, Other on-chip features include a programmable excitation current source, fusible current control, and a bias voltage generator, which can be used to set the common-mode voltage of a channel to AVDD/2.

 GX7793 Key Features:

- Power consumption: 355µA (typical)

- Update rate: 4.17Hz to 940Hz

- 3 differential inputs

- 2.7V~5.25V supply power supply

- TSSOP-16 package