Ultra-small integrated AFE for wearable optical heart-rate monitoring and SpO2
AFE4950
Product details
Parameters
Package | Pins | Size
Features
- Supports simultaneous & synchronized acquisition of up to 24 PPG and a single-lead ECG signal.
- Flexible allocation of 8 LED, 4 PD in each phase
- ECG signal chain:
- 1-lead ECG signal acquisition up to 2 kHz
- RLD output to drive a third electrode
- Input noise : 0.7 µV-rms
- Supports up to +/- 0.65 V differential DC offset and +/-0.55 V common mode range
- Programmable INA gain: 11, 21
- High-pass filter with quick saturation recovery
- Integrated 300 Hz anti-aliasing low pass filter
- AC, DC lead-off detect: 2.6-nA to 85-nA
- Low power continuous lead-on detection
- Impedance signal chain
- Continuous low-power monitoring of impedance between 2 electrodes
- 7 MΩ range
- 300 Ω noise on 620 kΩ
- PPG Transmitter:
- 8-Bit Programmable LED Current with range adjustable from 25 mA to 250 mA
- Mode to fire two LEDs in parallel
- Support of 8 LEDs in Common Anode configuration for SpO2, Multi-Wavelength HRM
- PPG Receiver:
- 2 parallel receivers (two sets of TIA/ filter)
- Supports 4 Time-Multiplexed Photodiode Inputs to each Receiver
- 8-bit Ambient Offset subtraction at each TIA input with 256 µA range
- 8-bit LED Offset Subtraction DAC with 64 µA range
- Automatic ambient cancellation and dynamic LED DC cancellation at TIA input
- Ambient rejection close to 100 dB up to 10 Hz
- Noise filtering with programmable bandwidth
- Trans-impedance Gain: 3.7 kΩ to 1 MΩ
- Accurate, Continuous Heart-Rate Monitoring:
- System SNR up to 109-dB at 16 µA PD current
- Low Current for Continuous Operation on a Wearable Device with a Typical Value: 15-µA for an LED, 20-µA for the Receiver
- External clock and internal oscillator modes
- Acquire data synchronized with system master clock
- FIFO with 256-sample Depth
- SPI, I2C interfaces: Selectable by pin
- 2.6-mm × 2.5-mm DSBGA, 0.4-mm Pitch
- Supplies: Rx:1.7-1.9V (LDO Bypass); 1.9-3.6V (LDO Enabled), Tx:3-5.5V, IO:1.7-RX_SUP
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Description
The AFE4950 device is an analog front-end (AFE) for synchronized signal acquisition of PPG and ECG signals. The device can also be used for optical bio-sensing applications, such as heart-rate monitoring (HRM) and saturation of peripheral capillary oxygen (SpO2). The ECG signal chain supports 2- and 3-electrode configurations and has an integrated Right leg drive (RLD) buffer. The ECG signal chain can also be used to do a continuous, low-power monitoring of the impedance between pair of electrodes.

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For all other applications, see our general-purpose RF-sampling AFEs.
Technical documentation
Type | Title | Date | |
---|---|---|---|
* | Datasheet | AFE4950 Ultra-Small, Integrated AFE for Wearable Optical Heart-Rate Monitoring, SpO2 and Electrical Bio-sensing datasheet (Rev. A) | Oct. 23, 2020 |
Technical articles | Offset correction improves the next generation of heart-rate smart watches | Aug. 24, 2015 | |
Technical articles | A new way to illuminate the human condition | Dec. 30, 2013 | |
Technical articles | Oximeter signaling: There’s more than meets the eye | Dec. 04, 2013 | |
Technical articles | Virtual hospital implementation using a worn health monitor | Nov. 13, 2013 |
Design & development
For additional terms or required resources, click any title below to view the detail page where available.Hardware development
Description
The AFE4950 evaluation module (EVM) is designed to expedite evaluation and system-development activities related to the AFE4950 product. AFE4950 is an analog front end (AFE) for synchronized signal acquisition of PPG and ECG signals. AFE4950 can also be used for optical biosensing applications, such (...)
Features
- Acquire data at up to 1000 SPS in evaluation mode
- USB-based power and PC application connectivity
- Access to all AFE4950 registers
- USB-based firmware upgrade option
Design tools & simulation
Features
- Leverages Cadence PSpice Technology
- Preinstalled library with a suite of digital models to enable worst-case timing analysis
- Dynamic updates ensure you have access to most current device models
- Optimized for simulation speed without loss of accuracy
- Supports simultaneous analysis of multiple products
- (...)
CAD/CAE symbols
Package | Pins | Download |
---|---|---|
DSBGA (YBG) | 36 | View options |
Ordering & quality
- RoHS
- REACH
- Device marking
- Lead finish/Ball material
- MSL rating/Peak reflow
- MTBF/FIT estimates
- Material content
- Qualification summary
- Ongoing reliability monitoring
Recommended products may have parameters, evaluation modules or reference designs related to this TI product.
Support & training
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