AFE4410 Ultra-Small, Integrated AFE With FIFO for Wearable, Continuous Optical Heart-Rate Monitoring and Biosensing
SBAS832 – May2017
- Accurate, Continuous Heart-Rate Monitoring:
- Up to 100-dB Dynamic Range for Accurate Heart-Rate Detection
- Low Current for Continuous Operation on a Wearable Device With a Typical Value:
- 30 µA for an LED, 25 µA for the Receiver
- 4 LEDs in Common Anode Configurations
- 8-Bit Programmable LED Current to 200 mA
- Mode to Fire Two LEDs in Parallel
- Programmable LED On-Time
- Simultaneous Support of 3 LEDs for Optimized SpO2, HRM, 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,
- Supports 3 Time-Multiplexed PD Inputs
- 24-Bit Representation of Current Input From PD in Twos Complement Format
- Individual DC Offset Subtraction DAC
(Up to ±126-µA Range) at TIA Input for Each LED, Ambient
- Digital Ambient Subtraction at ADC Output
- Transimpedance Gain: 10 kΩ to 2 MΩ
- Noise Filtering With Programmable Bandwidth
- Receiver Operates at Approximately 1-µA/Hz Sampling Rate (Example, 25 µA at 25 Hz)
- Hardware Power-Down Mode: Approximately 0-µA Current
- Flexible Pulse Sequencing and Timing Control
- Clocking Via External Clock or Internal Oscillator
- FIFO With 128-Sample Depth:
- Programmable Partitioning Across Phases
- Pin-Selectable I2C, SPI Interface
- Operating Temperature Range: –20°C to +70°C
- 2.6-mm × 2.1-mm, 0.4-mm Pitch DSBGA Package
- Tx: 3 V to 5.25 V
- Rx: 1.8 V to 1.9 V (LDO Bypass),
2.0 V to 3.6 V (LDO Enabled)
- IO: 1.7 V to Rx_SUP
- Optical Heart-Rate Monitoring (HRM) for Wearables, Hearables
- Heart-Rate Variability (HRV)
- Pulse Oximetry (SpO2) Measurements
- Maximum Oxygen Consumption (VO2 Max)
The AFE4410 is an analog front-end for optical biosensing applications, such as heart-rate monitoring (HRM). The device supports up to four switching light-emitting diodes (LEDs) and up to three photodiodes (PDs). The current from the photodiode is converted into voltage by the transimpedance amplifier (TIA) and digitized using an analog-to-digital converter (ADC). The ADC code is stored in a 128-sample first in, first-out block (FIFO) with programmable depth. The FIFO can be read out using either an I2C interface or a serial peripheral interface (SPI). The AFE also has a fully integrated LED driver with 8-bit current control. The device has high dynamic range transmit-and-receive circuitry offering a dynamic range of up to 100 dB that enables accurate heart-rate sensing. The AFE achieves extremely low current levels by operating an ultralow power (ULP) mode set by using the ENABLE_ULP register bit.
|PART NUMBER||PACKAGE||BODY SIZE (NOM)|
|AFE4410||DSBGA (30)||2.60 mm × 2.10 mm|
- For all available packages, see the package option addendum at the end of the datasheet.
Simplified Block Diagram
4 Device and Documentation Support
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4.2 Electrostatic Discharge Caution
This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.
ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.
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