Sigma-Delta ADCs step up acquired signal quality

Sigma-Delta ADCs step up acquired signal quality

New Products |
By Graham Prophet

The AD7768 series includes a power scalable modulator and digital filter on each channel to enable the synchronized, precise measurement of both ac and dc signals in instrumentation applications, including modular data acquisition, audio test, and asset condition monitoring. The high throughput, fast settling response, and simultaneous sampling of the AD7768 series enables faster test times, which reduces testing costs and allows more efficient instrumentation design. The AD7768 series’ high channel count provides healthcare devices, such as clinical vital signs monitoring equipment, with the means to significantly expand channel density while maintaining low power and high input bandwidth. The converters also deliver improved power quality monitoring through the ability to detect harmonic distortion over a wider bandwidth for detection and diagnosis of grid imbalance. A scalable, easy-to-configure layout also allows system designers to save additional time and cost by using a single converter series across multiple equipment platforms, performance points and measurement ranges.

The 24-bit, 8-channel AD7768 and the 24-bit, 4-channel AD7768-4 claim a 6-dB dynamic range advantage over the nearest competing products and deliver the best-available integral non-linearity (INL) performance across the widest available bandwidth, in addition to achieving 10 times better offset, a 30 times reduction in gain error, and a 2 times improvement in gain drift.


Next; feature listing, price and availability

– Precision ac and dc performance

– 8-/4-channel simultaneous sampling

256 kSPS maximum ADC output data rate per channel

108 dB dynamic range

110.8 kHz maximum input bandwidth (−3 dB bandwidth)

−120 dB total harmonic distortion (THD) typical

±2 ppm of full-scale range (FSR) integral nonlinearity (INL), ±50 µV offset error, ±30 ppm gain error

– Optimized power dissipation vs. noise vs. input bandwidth

Selectable power, speed, and input bandwidth (BW) modes

– Fast: highest speed; 110.8 kHz BW, 51.5 mW per channel

– Median: half speed, 55.4 kHz BW, 27.5 mW per channel

– Eco: lowest power, 13.8 kHz BW, 9.375 mW per channel

Input BW range: dc to 110.8 kHz

Programmable input bandwidth/sampling rates






Output Data Rate


Channel Count


Price Each Per 1,000



256 kSPS





64-lead LQFP


256 kSPS





64-lead LQFP


256 kSPS





64-lead LQFP


Analog Devices;



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