GXSC Analog-to-Digital Converter Replaces AD7609 in Power Line Monitoring System

Power lines serve as the medium for electricity transmission and distribution. Their monitoring system, powered by solar energy and integrated with wireless communication technology, functions as a remote monitoring system. It primarily collects real-time data such as video imagery, micro-meteorological conditions, tower inclination, and anti-theft alarms from transmission lines, transmitting this information to the monitoring center. This system significantly impacts power supply reliability, power quality, and the safety of electrical equipment.

This paper introduces the application of a GXSC eight-channel, 18-bit, 200kSPS true differential synchronous sampling ADC replacing the AD7609 in power line monitoring systems. This chip‘s performance advantages—maximum throughput of 200kS/s, high precision, true differential input, high noise immunity, and high integration—make it highly suitable for the multi-parameter synchronous acquisition demands of power line monitoring. It finds extensive application in distribution network monitoring, industrial power monitoring, and renewable energy grid integration monitoring scenarios.

Harmonic components and minute current fluctuations in power lines demand high resolution and linearity from ADCs. The GXSC ADC achieves 18-bit full resolution with no missing codes, delivering outstanding linearity and low noise. It precisely captures analog signal variations at the millivolt or even microvolt level, faithfully reproducing minute fluctuations in power line voltage and current. This meets the requirements for power quality monitoring and precision energy metering.

The GXSC ADC is a low-power successive approximation ADC supporting simultaneous sampling across eight true differential input channels. Each channel achieves a conversion rate of up to 200kSPS. Powered solely by a 5V supply, the chip supports conversion of true bipolar differential input signals ranging from ±20V to ±10V. To simplify PCB design for data acquisition systems, the chip integrates a flexible, high-precision reference voltage generator and buffer. It incorporates an input buffer with 1MΩ input impedance and an anti-aliasing filter, enabling direct acquisition of analog signals.

The device supports parallel or serial modes, configurable via different hardware pin connections. This feature creates multiple connection options for interfacing the device with FPGAs, microprocessors, or DSPs. Key features are outlined below:

64-pin LQFP package, compatible with the imported AD7609.

Dual 16-bit successive approximation ADC

True bipolar analog inputs

Input range: ±10V, ±5V, ±2.5V

 Low power consumption: 210mW (internal reference)

On-chip reference voltage source and buffer

Parallel and serial interface modes

High-speed serial interface compatible with SPI protocol

80-pin LQFP package

Analog input channels provide 4kV ESD rating

ENOB: 14.9 bits (typical)

 SNR: 91.8dB (typical)

SINAD: 91.5dB (typical)

SFDR: -110dB (typical)

INL: ±2.5LSB (typical)

DNL: ±0.75LSB (typical)

Operating power consumption: 120mW (internal reference)

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