GXSC Analog-to-Digital Converter Hardware and Software Replacement with ADS1274 for Vibration Analysis

Vibration analysis technology achieves early fault warning, type identification, and lifespan prediction by collecting and analyzing equipment vibration signals, reflecting the health status of the equipment. It primarily involves the "ultra-high precision, wide frequency range, and low-noise" acquisition of vibration signals. The workflow of the vibration analysis system is "vibration signal acquisition—signal conditioning—analog-to-digital conversion—data transmission—feature extraction—fault diagnosis," with the "analog-to-digital conversion" step being crucial. This paper recommends using a 24-bit synchronous sampling analog-to-digital converter for vibration analysis to ensure accurate vibration signal acquisition in complex industrial environments.

The GXSC is a 4-channel synchronous sampling 24-bit Δ-Σ analog-to-digital converter, supporting a data sampling rate of up to 144kSPS. It enables extremely precise quantification of input analog signals, effectively enhancing measurement accuracy and system resolution.

Four operation modes are available:  

- **High-Speed (HS) Mode**: Fastest speed, with a 37MHz clock achieving 144kSps, -3dB bandwidth of 70kHz.  

- **High Precision (HR) Mode**: Highest accuracy, with SNR up to 111.7dB and THD down to -122.9dB, consuming only 20.8mW/channel.  

- **Low Power (LP) Mode**: Same output rate as HR mode but with nearly halved power consumption.  

- **Low-Speed (LS) Mode**: Suitable for low-speed acquisition, with power consumption as low as 2.7mW/channel.  

The chip is directly controlled via pins without requiring register programming, making it user-friendly for customers.

The chip employs a high-order multi-bit Delta-sigma modulator, which shapes the in-band noise and filters it out through an on-chip digital decimation filter, resulting in extremely low in-band noise power. Two types of on-chip digital filters are available: a high-bandwidth FIR filter with an effective bandwidth reaching 90.6% of the Nyquist bandwidth, while maintaining in-band ripple below ±0.005dB; and a low-latency SINC filter that produces stable data output within 6 cycles and offers superior noise performance. The characteristics are as follows:

• 8-channel synchronous sampling with a data rate of up to 144kSps

• High-bandwidth FIR filter or low-latency SINC filter available

• Low power consumption: HS mode: 34.0mW/channel; HR mode: 20.8mW/channel; LP mode: 10.9mW/channel; LS mode: 2.7mW/channel;

• Rail-to-rail input common-mode level

• Common-mode rejection ratio: 116dB

• Analog power supply: 5V; Digital power supply: 1.8V

• I/O Power Supply: 1.8V~3.3V

• SPI or frame synchronization interface, supports daisy chain mode

• ESD Rating: HBM ±2kV, CDM ±2kV; Latch-up ±600mA

• Operating temperature range: -40°C to +85°C