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Analog Front End ICs Manufacturers | Heart rate monitoring ICs

This page describes analog front end basics including its modules. It mentions list of Analog Front End ICs Manufacturers or vendors used for heart rate monitoring.

Introduction: Heart rate measurement is very essential to detect various diseases due to fast heart rate (tachycardia), slow heart rate (bradycardia) and changing heart rate (arrhythmia). Heart rate monitors have been developed for this measurement. AFEs (Analog Front Ends) are used in such monitors as they can directly perform signal conditioning on received signals from sensors placed on or around heart.

The figure depicts use of Analog Front End (AFE) in health monitoring system. As shown, AFE consists of analog amplifier, filters, sample and hold circuits, ADCs (Analog to Digital Converters), Instrumentation Amplifiers (InAmp) etc.

Health Monitoring System

Analog amplifier : It is implemented using Operational amplifier (op-amp). TIA (Trans-Impedance Amplifier) converts current to voltage and amplifies output as per desired value.
Filters : These modules are used to pass wanted frequencies and block unwanted frequencies.
Sample and Hold Circuits : These circuits take voltage samples as input (one at a time) and holds them for certain duration and then output them. These circuits typically use analog switch, capacitor and buffer.
ADCs : These modules convert analog signals to digital signals (2's complement form). Provide interface between analog sensors and microcontroller. Analog sensors are used as per various functionalities such as accelerometers, flex sensors, temperature sensors etc.
Instrumentation Amplifier : These are differential operational amplifiers which provide high input impledances.

LEDs and Photodiodes for Heart Rate and SpO2 measurement

LEDs and Photodiodes : These Opto electronic components are used for the measurements of heart rate, SpO2 and other health related parameters. Refer article on LEDs and Photodiodes for Health Monitoring system >>.

Analog Front End ICs Manufacturers

Following table mentions manufacturers or vendors of analog front end ICs used in heart rate monitoring systems.

Manufacturers Description
Texas Instruments Model : AFE4403
The device consists of low noise receiver, LED, Photodiode, Oscillator, ADC, digital filter, amplifier, SPI interface etc. Refer product datasheet at ti.com website.
Applications : pulse oximeter, photometry, optical heart rate monitoring etc.
Dialog Semiconductor (Acquired by Renesas Electronics Corporation) Model : SLG47004
Features : Houses two Op-amps with configurable bandwidth, two SPST analog switches, three analog comparators, three oscillators, Macrocells, I2C interface, built in analog temperature sensor etc.
Analog Devices Models : AD5940/AD5941
The products have various features. Refer datasheets at analog.com website for all the features, functional block diagrams, pin outs and other technical specifications.
Maxim Integrated Product : MAX86170A
Features : It houses both transmit/receive channels used as optical data acquisition system. Transmit part supports 6 LED driver outputs. Receive part supports 2 low noise front ends with independent ADCs (20 bits) in each chain and light cancellation circuits. Refer website maximintegrated.com for more information.
NXP Semiconductors Company develops healthcare AFE reference platforms. Refer Application note AN4059 on heart rate monitoring and ECG fundamentals. It mentions analog front end ICs along with implementation diagrams. Visit nxp.com for AFE product series.

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