Application scheme of GXSC GX7793 compatible with AD7793 in high-precision temperature control equipment

Temperature control technology has become an important part of various activities such as industry, agriculture, scientific research, aerospace, and people‘s lives. Especially in the fields of scientific research, aerospace, biomedicine, precision instruments, etc., the requirements for temperature control accuracy are extremely high, sometimes extremely demanding.

High precision temperature control equipment is based on MCU, ADC, and OPA as core chips, and has the characteristics of high precision, simple structure, and good stability. This article introduces the application of a domestically produced ADC in high-precision temperature control equipment. The GX7793 has the advantages of high integration, stable performance, and high cost-effectiveness, and is compatible with the AD7793.

The GX7793 has high resolution and low noise, so the requirements for the front-end anti aliasing filter are greatly reduced, with a maximum of 16/24 bits. Integrated with programmable gain amplifier (PGA) and low drift on-chip reference voltage source, it can provide high-precision measurement solutions for bridge sensors, thermocouples, and resistance temperature devices (RTDs).

GX7793 includes a low-noise PGA, with selectable gains of 1, 2, 4, 8, 16, 32, 64, and 128, a Δ - ∑ modulator, and a digital filter. A low drift 1.17V or 2.5V reference voltage source is integrated on the chip, and two matching excitation current sources (IEXC) are provided for precise RTD measurement. The output data rate of this device can be configured from 4.17SPS to 890SPS, with 50Hz/60Hz simultaneous suppression options, and a burnout current source is provided at the analog input terminal of the sensor connection diagnosis.

The parameters of GX7793 are as follows:

Offset drift: 5nV/C (gain=128)

Gain drift: 1ppm/℃

• Integral nonlinearity: 2ppm

4 differential inputs, internal or external clock

• Adopting a 16 pin TSSOP package

The working temperature is within the range of -40 ℃ to+125 ℃