With the rapid development of precision medicine and wearable health monitoring technologies, the acquisition of bioelectrical potentials (such as electroencephalogram [EEG] and electrocardiogram [ECG]) imposes stringent requirements on the performance of analog-to-digital converter (ADC) chips. Biomedical signals are generally characterized by weak amplitude, low-frequency properties, and susceptibility to power line interference, while devices face development challenges such as miniaturization, low power consumption, and multi-channel compatibility. The Corebai Micro CBM24AD99Q, a low-noise 24-bit ADC chip specifically designed for EEG and bioelectrical potential measurements, adopts a core approach of "precise acquisition + high integration + flexible adaptation." This addresses the limitations of traditional general-purpose ADC chips in balancing precision, integration, and scenario adaptability, making it the preferred solution for overcoming the pain points in medical signal acquisition.

The chip adopts a 24-bit Δ-Σ architecture, with input reference noise as low as 1μVPP (70Hz bandwidth) and input bias current as low as 300pA. Coupled with a 121dB signal-to-noise ratio (SNR) and 8ppm integration nonlinearity (INL), it accurately reconstructs weak signal details such as μV-level EEG and fetal ECG. It also offers 4/6/8 channel version options, with each channel equipped with an independent low-noise programmable gain amplifier (PGA), supporting 1, 2, 4, 6, 8, 12, and 24 times programmable gain. The data rate ranges from 250SPS to 16kSPS.

The CBM24AD99Q chip features a medical-grade anti-interference design with a Common Mode Rejection Ratio (CMRR) of-110dB, effectively suppressing 50/60Hz power line interference. It incorporates a built-in BIAS bias driver circuit and SRB1/2 reference electrode pins to further mitigate common-mode interference.

The product integrates a programmable gain amplifier, internal voltage reference, oscillator, lead drop detection module, and temperature sensor, eliminating the need for additional external core components. It adopts a compact TQFP-64 (10mm×10mm) package. The device is compatible with ADS1299 pins and programming, supports SPI serial interface, and enables high-channel system expansion through daisy-chain cascading. It offers both continuous and single-shot conversion modes, suitable for real-time monitoring and scheduled sampling scenarios. In terms of operating temperature range, the CBM24AD99Q covers-40°C to +85°C, with an ESD rating of ±1000V and a junction-to-environment thermal resistance of 46.2°C/W, meeting the reliability requirements of medical devices in various scenarios such as operating rooms and outdoor emergency situations.

Typical application scenarios

Electroencephalogram (EEG) research: Low-noise characteristics are optimized for μV-level EEG signal acquisition, with multi-channel configuration supporting multi-lead brain function monitoring, facilitating epilepsy diagnosis and brain science research.

Fetal electrocardiogram (ECG): Featuring high CMRR and low-noise design, it effectively filters maternal signal interference to accurately capture the weak fetal ECG signals, ensuring the accuracy of prenatal monitoring.

Bispectral Index (BIS) monitoring: The 16kSPS high sampling rate meets the real-time monitoring requirements for anesthesia depth, rapidly responds to signal changes, and provides precise data support for surgical anesthesia.