GXSC ADC Replacing AD7656 for Multi-Axis Servo Control

The multi-axis servo control system serves as the driving force behind high-end manufacturing and is widely used in scenarios such as CNC machine tools, robots, and electronic packaging equipment. It primarily achieves high-precision synchronization and coordination of multi-axis motion, such as the three-axis linkage processing in CNC machine tools, where real-time matching of position and speed signals across axes is required. A deviation exceeding 0.01mm may result in workpiece rejection. The fulfillment of this requirement relies on the precise acquisition of key signals like motor position, speed, and current.

The six-channel 16-bit 250kSPS synchronous sampling ADC of GXSC perfectly addresses the data acquisition challenges in multi-axis servo control. Its six-channel synchronous sampling design utilizes a unified clock to trigger the sample-and-hold circuits, minimizing inter-channel synchronization errors. Additionally, the 16-bit high precision and wide dynamic range further enhance control accuracy.

The GXSC ADC operates solely on a 5V power supply and supports true bipolar input signals of +10V and +5V. With its built-in calibration algorithm, the product significantly enhances both dynamic and static performance. In terms of dynamic performance, it achieves a signal-to-noise ratio (SNR) of up to 90dB and a spurious-free dynamic range (SFDR) of 100dB. For static performance, it boasts a bipolar zero-level error as low as +2LSB and linearity below 1LSB. The device supports both parallel and serial modes, configured via different hardware pin connection patterns. This feature creates multiple connection conditions for interfacing the device with microprocessors or DSPs.

To simplify the PCB design of the data acquisition system, the GXSC ADC incorporates an input buffer with a 1MΩ input impedance and an anti-aliasing filter for direct analog signal acquisition. It also integrates a highly configurable high-precision reference voltage generator and buffer.

Performance Advantages of GXSC ADC:

Supports pin-to-pin drop-in replacement for AD7656

The product dimensions, pinout, functionality, and timing are compatible with the reference product. It operates on a single 5V power supply and is compatible with ±15V power pins, making it easy to integrate into applications

Higher signal-to-noise ratio, higher linearity

Lower bipolar zero-level error, lower positive and negative full-scale error

Higher channel isolation

ENOB: 14.5 Bits (Typical Value)

SNR: 89.5 dB (typical value)

SNDR: 89 dB (typical value)

SFDR: -103 dB (typical value)

THD: -100dB (typical value)

INL: ±1LSB (typical)

DNL: ±0.5 LSB (typical)

Operating power consumption: 110mW (internal reference)

Operating temperature: -55°C to +125°C

It adopts a 64-pin QFP package, available in both ceramic and plastic enclosures