Ultra-low-power integrated AFE for wearable optical, electrical biosensing
Product details
Parameters
Features
- Synchronized PPG, ECG signal acquisition at data rates up to 1 kHz
- ECG signal chain:
- Standalone ECG acquisition up to 4 kHz
- Input bias: 1-lead ECG with RLD bias
- Programmable INA gain: 2.15 to 12.92
- Input noise (1 Hz to 150 Hz): 2.5 µVrms at 1 kHz, 1.25 µVrms at 4-kHz data rate
- AC, DC lead-off detect: 12.5-nA to 100-nA
- IEC 60601 Test report available on request
- PPG receiver:
- Supports three time-multiplexed PD inputs
- 24-Bit representation of current from PD
- DC offset subtraction DAC (Up to ±126-µA) at TIA input for each LED, ambient
- Digital ambient subtraction at ADC output
- Noise filtering with programmable bandwidth
- Transimpedance gain: 10 kΩ to 2 MΩ
- Dynamic range up to 100 dB
- Receiver operates in PPG-only mode at approximately 1-µA/Hz sampling rate
- Power-down mode: approximately 0 µA
- PPG transmitter:
- Four LEDs in common anode configuration
- 8-Bit LED current up to 200 mA
- Mode to fire two LEDs in parallel
- Programmable LED on-time
- Simultaneous support of three LEDs for SpO2, or multiwavelength HRM
- Average current of 30 µA adequate for a
typical heart-rate monitoring scenario:- 20-mA Setting, 60-µs pulse duration,
25-Hz sampling rate
- 20-mA Setting, 60-µs pulse duration,
- Clocking using an external or internal clock
- FIFO with 128-sample depth for ECG and PPG
- I2C, SPI interfaces: selectable by pin
- 2.6-mm × 2.1-mm, 0.4-mm Pitch DSBGA package
- Supplies:
- 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
- Rx: 1.8 V to 1.9 V (LDO bypass),
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Description
The AFE4900 device is an analog front-end (AFE) for synchronized electrocardiogram (ECG), photoplethysmogram (PPG) signal acquisition. 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 PPG signal chain supports up to four switching light-emitting diodes (LEDs) and up to three photodiodes (PDs). The LEDs can be switched on using a fully integrated LED driver. The current from the photodiode is converted into voltage by the transimpedance amplifier (TIA) and digitized using an analog-to-digital converter (ADC). The ECG signal chain has an instrumentation amplifier (INA) with a programmable gain that interfaces to the same ADC. A right-leg drive (RLD) amplifier set can be used to the bias for the ECG input pins. AC and dc lead-off detect schemes are supported. The ADC codes from the PPG and ECG phases can be stored in a 128-sample first in, first out (FIFO) block and read out using either an I2C or a serial programming interface (SPI) interface.
More Information
Full data sheet and other design resources are available. Request now
Technical documentation
Type | Title | Date | |
---|---|---|---|
* | Datasheet | AFE4900 Ultra-low Power, Integrated AFE for Wearable Optical, Electrical Bio-sensing with FIFO datasheet (Rev. B) | Jul. 30, 2019 |
Technical articles | Designing compact, efficient and high performing multiparameter patient monitors | Jun. 25, 2019 | |
Technical articles | No strings attached: Creating next-generation wireless patient monitors | Jun. 29, 2018 | |
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 |
Design & development
For additional terms or required resources, click any title below to view the detail page where available.Hardware development
Description
The AFE4403EVM is intended for evaluating the AFE4403 device. The fully integrated AFE is ideally suited for Pulse Oximeter and Heart rate monitoring applications and consists of low noise receive channel, the LED transmit section and diagnostics for sensor and LED fault detection. The AFE4403 has a (...)
Features
- DB9 pulse oximeter sensor cable support
- Acquire data at up to 3000 Hz in evaluation mode
- USB based power and PC application connectivity
- Access to all AFE4403 registers via an easy-to-use GUI
- USB-based firmware upgrade option
Description
The AFE44x0SPO2EVM is intended for evaluating AFE4400 and AFE4490 devices. The family of devices are fully integrated AFE ideally suited for Pulse Oximeter applications and consist of low noise receive channel, the LED transmit section and diagnostics for sensor and LED fault detection. The (...)
Features
- DB9 pulse oximeter sensor cable support
- Acquire data at up to 3000 Hz in evaluation mode
- USB based power and PC application connectivity
- Access to all AFE44x0 registers via an easy to use GUI
Description
The AFE4900 is an analog front end (AFE) for optical biosensing applications, such as heart-rate monitoring (HRM) and saturation of peripheral capillary oxygen (SpO2). The device supports four switching light-emitting diodes (LEDs) and three photodiodes. The current from the photodiode is converted (...)
Features
- Acquire data at up to 1000 SPS in evaluation mode
- USB-based power and PC application connectivity
- Access to all AFE4900 registers via an easy-to-use GUI
- 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
- (...)
Reference designs
Design files
CAD/CAE symbols
Package | Pins | Download |
---|---|---|
(YZ) | 30 | View options |
Ordering & quality
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- MSL rating/Peak reflow
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- Material content
- Qualification summary
- Ongoing reliability monitoring
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