Overview
The AFE4900YZR is an ultra-low-power integrated analog front-end (AFE) device designed by Texas Instruments for synchronized electrocardiogram (ECG) and photoplethysmogram (PPG) signal acquisition. It is particularly suited for wearable optical and electrical biosensing applications, including heart-rate monitoring (HRM) and saturation of peripheral capillary oxygen (SpO2) measurements. The device features a compact 2.6-mm × 2.1-mm DSBGA package with 30 pins, making it ideal for space-constrained wearable and hearable devices.
Key Specifications
| Parameter | Specification |
|---|---|
| Package | DSBGA (YZ), 30 pins |
| Operating Temperature Range | -20°C to 70°C |
| ECG Data Rate | Up to 4 kHz (standalone), up to 1 kHz (synchronized with PPG) |
| PPG Data Rate | Up to 1 kHz |
| INA Gain | Programmable: 2.15 to 12.92 |
| Input Noise (ECG) | 2.5 µVrms at 1 kHz, 1.25 µVrms at 4 kHz |
| Transimpedance Gain (PPG) | 10 kΩ to 2 MΩ |
| Dynamic Range (PPG) | Up to 100 dB |
| LED Current (PPG) | 8-Bit, up to 200 mA |
| Supply Voltages | Rx: 1.8 V to 1.9 V (LDO bypass), 2.0 V to 3.6 V (LDO enabled); Tx: 3 V to 5.25 V; IO: 1.7 V to Rx_SUP |
| Interface | I2C, SPI (selectable by pin) |
Key Features
- Synchronized PPG and ECG signal acquisition at data rates up to 1 kHz.
- ECG signal chain with standalone ECG acquisition up to 4 kHz, input bias with RLD, and programmable INA gain.
- PPG receiver supporting three time-multiplexed photodiode inputs, DC offset subtraction DAC, and digital ambient subtraction at ADC output.
- PPG transmitter with four LEDs in common anode configuration, 8-bit LED current control, and programmable LED on-time.
- FIFO with 128-sample depth for ECG and PPG, and I2C or SPI interfaces.
- AC and DC lead-off detection schemes.
- Low power consumption with power-down mode approximately at 0 µA.
Applications
- Synchronized PPG and ECG for blood pressure estimation.
- Heart-rate monitoring (HRM) for wearables and hearables.
- Heart-rate variability (HRV) measurements.
- Pulse oximetry (SpO2) measurements.
- Multiwavelength HRM and SpO2 measurements.
Q & A
- What is the primary function of the AFE4900YZR device?
The AFE4900YZR is an analog front-end (AFE) for synchronized electrocardiogram (ECG) and photoplethysmogram (PPG) signal acquisition. - What is the package type and size of the AFE4900YZR?
The device is packaged in a 2.6-mm × 2.1-mm DSBGA package with 30 pins. - What are the operating temperature ranges for the AFE4900YZR?
The operating temperature range is -20°C to 70°C. - What are the data rates for ECG and PPG signal acquisition?
ECG: up to 4 kHz (standalone), up to 1 kHz (synchronized with PPG); PPG: up to 1 kHz. - What is the range of programmable INA gain for the ECG signal chain?
The INA gain is programmable from 2.15 to 12.92. - How many LEDs and photodiodes are supported by the PPG signal chain?
The PPG signal chain supports up to four LEDs and up to three photodiodes. - What interfaces are available for data communication?
The device supports I2C and SPI interfaces, selectable by pin. - What is the power consumption in power-down mode?
The power consumption in power-down mode is approximately 0 µA. - What are some of the key applications of the AFE4900YZR?
Key applications include HRM for wearables and hearables, HRV measurements, and pulse oximetry (SpO2) measurements. - Does the device support lead-off detection?
Yes, the device supports AC and DC lead-off detection schemes.
