GXSC analog-to-digital converter replaces AD4115 for analog signal acquisition in rail transit

The simulated signals in rail transit scenarios cover multiple types such as voltage, current, temperature, pressure, and vibration, and require long-term stable collection under extreme conditions such as strong electromagnetic interference, wide temperature fluctuations, and mechanical vibrations. The simulated signal acquisition system for rail transit is responsible for real-time capture and conversion of key parameters of trains and equipment along the line. The accuracy of data directly determines the reliability of fault diagnosis and operation and maintenance decisions. This article recommends using GXSC low-power, low-noise 24 bit analog-to-digital converter, which can directly replace AD4115 for analog signal acquisition in rail transit.

The acquisition of simulated signals for rail transit requires coverage of multiple types of parameters such as voltage, current, and temperature. Traditional solutions require the use of a large number of discrete components, resulting in complex links and high failure rates. This analog-to-digital converter chip integrates 8 fully differential or 16 single ended analog front ends (AFEs), as well as key analog and digital signal conditioning modules. It can be configured with 8 independent settings for each analog input channel used, supporting 0.1% uncalibrated measurements of ± 10V and 0-20mA, with a single power supply of ± 40V input.

Early failures of rail transit equipment often manifest as subtle fluctuations in analog signals, requiring devices to have high precision and low noise characteristics to achieve early warning. This GXSC analog-to-digital converter provides good noise characteristics, providing nearly 16 bit noise free resolution at a conversion speed of 31.25kSPS, which is nearly a one bit improvement compared to industry competitors. Good noise is beneficial for the accuracy of small signals, especially in current acquisition applications, where smaller resistance sampling resistors can be used to reduce system power consumption while ensuring the same 0.1% accuracy.

The application characteristics of the GXSC analog-to-digital converter are introduced as follows:

Effective resolution: 17.9bits@62.5kSPS

Overall no calibration error: 0.07%

Offset as low as 0.5mV

High communication PSRR: 50dB@50Hz ~100kHz

High integration: Integrated benchmark temperature drift of 6ppm/℃ (Typ.), precision voltage divider resistor, integrated 2 ℃ high-precision temperature sensor

Support 50/60Hz simultaneous suppression

Support SPI CRC verification

Wire breakage detection: After input wire breakage, output returns to zero

Higher ESD/temperature rating: 2000V/1250V HBM/CDM

Digital power supply: 2.7V~5.5V; Simulated power supply: 4.5V~5.5V

Package: 6.0mm × 6.0mm QFN (40pin)

Working temperature range: -40 ° C to+125 ° C

In complex orbital environments, various frequencies of noise are coupled to the power supply of the analog-to-digital converter, which greatly tests the AC PSRR performance of the chip. The GXSC module has a power suppression capability of nearly 50dB in the frequency range of 1kHz to 100kHz, leading industry competitors. This feature ensures that the device can still accurately collect data in harsh interference environments.