SBAS861 August 2017 AFE4900


  1. 1Features
  2. 2Applications
  3. 3Description
  4. 4Device and Documentation Support
    1. 4.1Trademarks
    2. 4.2Electrostatic Discharge Caution
    3. 4.3Glossary
  5. 5Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • YZ|30
Orderable Information


  • 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 to 12
    • 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
  • 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
  • Clocking Using an External or Internal Clock
  • FIFO With 128-Sample Depth for ECG and PPG
  • I2C, SPI Interfaces: Selectable by Pin
  • Operating Temperature Range: –20°C to +70°C
  • 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


  • Synchronized PPG, ECG for Blood Pressure Estimation
  • HRM for Wearables, Hearables
  • Heart-Rate Variability (HRV)
  • Pulse Oximetry (SpO2) Measurements


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.

Device Information(1)

AFE4900 DSBGA (30)2.60 mm × 2.10 mm
  1. For all available packages, see the package option addendum at the end of the datasheet.


Simplified Block Diagram

AFE4900 fbd_sbas857.gif

Device and Documentation Support


All trademarks are the property of their respective owners.

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.


SLYZ022TI Glossary.

This glossary lists and explains terms, acronyms, and definitions.