AFE4900

ACTIVE

Ultra-low-power integrated AFE for wearable optical, electrical biosensing

Product details

Applications 1-lead ECG, Optical-HRM Number of input channels 3 Resolution (Bits) 22 Number of LEDs 4 Interface type I2C, SPI Operating temperature range (°C) -20 to 70 Rating Catalog
Applications 1-lead ECG, Optical-HRM Number of input channels 3 Resolution (Bits) 22 Number of LEDs 4 Interface type I2C, SPI Operating temperature range (°C) -20 to 70 Rating Catalog
DSBGA (YZ) 30 4.8 mm² 2.4 x 2
  • 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
  • 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
  • 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
  • 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

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.

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.

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AFE4950 ACTIVE Ultra-small integrated AFE for wearable optical heart-rate monitoring and SpO2 ECG+PPG AFE with integrated high-pass, low-pass filters optimized for dry electrodes.

Technical documentation

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Type Title Date
* Data sheet AFE4900 Ultra-low Power, Integrated AFE for Wearable Optical, Electrical Bio-sensing with FIFO datasheet (Rev. B) PDF | HTML 30 Jul 2019
Technical article Designing compact, efficient and high performing multiparameter patient monitors PDF | HTML 25 Jun 2019
Technical article No strings attached: Creating next-generation wireless patient monitors PDF | HTML 29 Jun 2018

Design & development

For additional terms or required resources, click any title below to view the detail page where available.

Evaluation board

AFE4403EVM — AFE4403 Integrated AFE for Heart-Rate Monitors and Pulse Oximeters Evaluation Module

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 (...)

User guide: PDF
Not available on TI.com
Evaluation board

AFE4490SPO2EVM — AFE4490 Integrated Analog Front End (AFE) for Pulse Oximeters Evaluation Module

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 (...)

User guide: PDF
Not available on TI.com
Evaluation board

AFE4900EVM — AFE4900 ultra-low-power integrated AFE for wearable optical, electrical biosensing evaluation module

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 (...)

Simulation tool

PSPICE-FOR-TI — PSpice® for TI design and simulation tool

PSpice® for TI is a design and simulation environment that helps evaluate functionality of analog circuits. This full-featured, design and simulation suite uses an analog analysis engine from Cadence®. Available at no cost, PSpice for TI includes one of the largest model libraries in the (...)
Reference designs

TIDA-01580 — Wireless ECG, SpO2, PTT and heart rate monitor reference design for medical and consumer wearables

This reference design is a simple, wearable, multi-parameter, patient monitor that uses a single-chip, biosensing front end, AFE4900, for synchronized electrocardiography (ECG) and photoplethysmography (PPG) measurements. The measured data is transferred to a remote location using CC2640R2F (...)
Design guide: PDF
Schematic: PDF
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DSBGA (YZ) 30 View options

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