GXSC A/D Converter Replaces AD7124 in Smart Field Transmitters

Against the backdrop of the full-scale advancement of Industry 4.0 and smart manufacturing, smart field transmitters serve as the front-end sensing devices for industrial process control. They convert physical quantities such as temperature, pressure, liquid level, flow, and weight into standard electrical signals, enabling digital transmission, fault diagnosis, and remote calibration. The GXSC 24-bit, 16-channel, highly integrated analog-to-digital converter is specifically designed for industrial precision measurement, meeting the application requirements of high-precision industrial transmitters.

The GXSC analog-to-digital converter integrates multiple functions to reduce system costs and component count in sensor measurement applications. It features a low-noise, programmable-gain amplifier, a single-cycle steady-state digital filter, and an internal oscillator. The chip also provides a built-in low-drift voltage reference and two matched programmable excitation current sources. The input multiplexer supports eight differential inputs; additionally, the multiplexer integrates sensor burnout detection, thermocouple voltage bias, system monitoring, and general-purpose digital I/O. The PGA offers selectable gain up to 128 V/V.

These features provide a complete front-end solution for sensor measurement applications, including thermocouples, thermistors, and resistance temperature detectors, as well as other small-signal measurements, such as bridge-type sensors. The digital filter stabilizes within a single cycle to support fast channel switching when using the input multiplexer and provides data rates up to 19.2 kSPS. For certain data rates, the filter suppresses 50 Hz and 60 Hz interference. Its key performance advantages are as follows:

• Effective resolution: 23 bits

• Number of channels: 16 single-ended / 8 differential pairs

• Output rate: Up to 19.2 kSPS

• High integration:

› Integrated internal reference: 8 ppm/°C temperature drift, 2.5 V

› Programmable differential amplifier (integrated high-impedance PGA): 0.02% initial accuracy

› Integrated 2-channel IDACs with 0.1% matching

› Integrated bias voltage and open-circuit detection

› Integrated temperature sensor with 2°C accuracy

• Supports simultaneous 50/60 Hz suppression

• Single-cycle settling and automatic channel scanning

• Supports SPI CRC verification

• Digital supply: 2.7 V to 5.25 V

• Analog Power Supply: Unipolar (2.7V–5.25V) & Bipolar (±2.5V)

• Package: 5.00mm × 5.00mm QFN (32-pin)

• Operating Temperature Range: –40°C to +125°C