ADC GX1291 Compatible ADS1291 for Portable Heart Rate Monitor

In a portable heart rate monitoring system, the lower the power consumption and the higher the stability of the system, the better the user experience. Therefore, the hardware of the system should be streamlined as much as possible and a low-power chip should be selected. The system hardware mainly consists of a front-end circuit module to collect the human body‘s ECG signals, and carry out appropriate amplification and filtering to extract the weak ECG signals, and then convert the analog voltage signals into digital signals through the AD sampling function.

AD sampling is very important because it is necessary to convert analog signals into digital signals and then process the data. The low-power, single-channel, 24-bit bioelectric measurement front-end analog chip GX1291 integrates all the features of a portable, low-power heart rate application, with a fast conversion rate and accurate sampling values. The chip has a built-in single-channel 24-bit Delta-Sigma (ΔΣ) analog-to-digital converter, a programmable gain amplifier, an internal reference and an oscillator, which effectively overcomes the drift and noise interference of the measurement signals and improves the measurement accuracy.

Application advantages in GX1291 heart rate monitor:

- Low power consumption of 420μW;

- Input reference noise: 8μVPP (150Hz BW, G=6); input bias current: 200pA;

- Data rate: 125SPS to 16kSPS; Common mode rejection ratio CMRR: 120dB;

- Programmable Gain: 1, 2, 3, 4, 6, 8, 12, 16, 24, 32, 64, 96;

- Oscillator initial accuracy: ±0.5% (25℃), temperature drift ±1% (-40℃~85℃);

- Unipolar power supply: analog: 2.7V to 3.6V; digital: 1.7V to 3.6V;

- Built-in right leg drive amplifier, lead detection and test signal, built-in pacing signal output and detection circuit;

- Flexible conversion between low-power mode and standby mode, SPI-compatible serial interface;

- Operating temperature range: -40℃ to 125℃;

The GX1291 has a flexible input multiplexer that can be independently connected to internally generated signals for test, temperature, and disconnection detection; it has a data rate of up to 16kSPS and added PACE detection. Using the GX1291 as a front-end analog can streamline the design and size of hardware circuits, effectively reducing design costs, and GXSC can provide full technical support.