Texas Instruments’ ADS1299 24-bit, eight-channel electroencephalography (EEG) analog front end (AFE) emerges as the first simultaneously sampling EEG AFE with input-referred-noise as low as 1 mV p-p (see the figure). This, according to the company, is more than 75% lower than the alternative EEG AFEs.
Providing non-invasive brainwave monitoring, the device functions in EEG equipment to monitor bispectral index, evoked potentials, and event-related potentials to diagnose brain injuries, strokes, and sleep disorders. It’s also viable for use in ultra-high performance diagnostic and research-grade electrocardiogram (ECG) equipment. And, with an eye on the eternal race to save space, the device trims board space by 70% while reducing the bill of materials by 40% when used in a 32-electrode EEG.
Integration levels are pretty impressive, counting eight low-noise programmable gain amplifiers, eight high-resolution analog-to-digital converters, a bias amplifier, an oscillator, and a reference. Specs are equally notable. These include an input-referred noise figure as low as 1 mVp-p at 70-Hz bandwidth and a common mode rejection ratio of –120 dB.
The ADS1299 is pin compatible with the ADS1298 family’s eight-channel ADS1298, ADS1298R, and ADS1198, the six-channel ADS1296, ADS1296R, and ADS1196, and the four-channel ADS1294, ADS1294R, and ADS1194. A performance demonstration kit, the ADS1299EEG-FE, includes evaluation software, analysis tools like an oscilloscope, FFT and histogram displays, flexible input configurations; optional external reference circuits. It also can export data in basic test files for post processing. Also, an IBIS model to verify board signal integrity requirements is available.
Residing in a 10- by 10-mm quad flat pack (QFP), price for the ADS1299 is $36 each in 1000-piece quantities.