Data Acquisition - Analog Front End (AFE)

Part Number	Description / PDF	Quantity
AFE1103E Burr-Brown (Texas Instruments)	DIGITAL SLIC, 1-FUNC, CMOS	1816
AFE1205E Burr-Brown (Texas Instruments)	DIGITAL SLIC, 1-FUNC, CMOS	6870
AFE2126E Burr-Brown (Texas Instruments)	DIGITAL SLIC, 1-FUNC	2194
AFE1105E/1K Burr-Brown (Texas Instruments)	DIGITAL SLIC, 1-FUNC, CMOS	6000
AFE1105E Burr-Brown (Texas Instruments)	DIGITAL SLIC, 1-FUNC, CMOS	2523
AFE1144E Burr-Brown (Texas Instruments)	DIGITAL SLIC, 1-FUNC	48
AFE1224E Burr-Brown (Texas Instruments)	DIGITAL SLIC, 1-FUNC	1672
AFE1124E Burr-Brown (Texas Instruments)	DIGITAL SLIC, 1-FUNC	369

Data Acquisition - Analog Front End (AFE)

1. Overview

Analog Front End (AFE) ICs are critical components in data acquisition systems, serving as the interface between analog sensors/transducers and digital processing units. They perform signal conditioning, amplification, filtering, and analog-to-digital conversion (ADC) driving functions. AFEs ensure signal integrity and measurement accuracy in applications ranging from medical devices to industrial automation, playing a pivotal role in modern precision electronics.

2. Major Types and Functional Classification

Type	Functional Features	Application Examples
Precision AFE	Low noise, high linearity, programmable gain amplifiers (PGA)	Medical imaging equipment, precision weighing scales
High-Speed AFE	Wide bandwidth (>100MHz), fast settling time	Ultrasound systems, radar receivers
Integrated AFE	Complete signal chain in single chip (PGA + ADC + DSP)	Smart sensors, IoT edge devices
Isolated AFE	Galvanic isolation with >5kV rating	Power grid monitoring, industrial safety systems

3. Structure and Composition

Typical AFE architecture includes:

Programmable Gain Amplifier (PGA) for signal scaling
Anti-aliasing filter (low-pass/band-pass)
ADC driver amplifier with fast transient response
Reference voltage generator
Digital control interface (I2C/SPI)
Optional isolation barriers (magnetic/optical)

Advanced designs integrate calibration circuits and fault detection modules.

4. Key Technical Specifications

Parameter	Description	Importance
Effective Number of Bits (ENOB)	Actual ADC resolution considering noise/distortion	Determines measurement accuracy
Signal-to-Noise Ratio (SNR)	Ratio of desired signal to background noise (dB)	Impacts dynamic range
Input Referred Noise	Amplifier noise converted to input equivalent (nV/ Hz)	Limits minimum detectable signal
Common-Mode Rejection Ratio (CMRR)	Ability to reject common-mode interference (dB)	Essential for noisy environments
Power Supply Rejection Ratio (PSRR)	Noise suppression from power rails (dB)	Ensures stable operation

5. Application Fields

Major application areas include:

Medical: ECG/EKG machines, blood glucose monitors
Industrial: Programmable logic controllers (PLCs), vibration sensors
Communications: Software-defined radios, optical transceivers
Automotive: Battery management systems, LiDAR receivers
Consumer: Smart wearables, voice assistants

6. Leading Manufacturers and Products

Manufacturer	Representative Product	Key Features
Analog Devices	AD7768	24-bit Sigma-Delta ADC with 2 V offset error
Texas Instruments	ADS1298	8-channel ECG frontend with built-in lead-off detection
STMicroelectronics	LTC2358	18-bit SAR ADC with 1MSPS throughput
NXP Semiconductors	MCP3911	6-channel energy measurement AFE with harmonic analysis

7. Selection Guidelines

Key considerations when selecting AFEs:

Match ADC resolution with system accuracy requirements
Evaluate bandwidth requirements vs. power consumption trade-offs
Consider integration level (discrete vs. system-on-chip)
Verify temperature stability (-40 C to +125 C range)
Assess digital interface compatibility (SPI/I2C speed)
Check for required certifications (medical/industrial safety)

8. Industry Trends

Current development trends include:

Increasing integration with AI acceleration for edge processing
Sub-1V supply operation for IoT devices
Emerging wide bandgap (GaN/SiC) compatible isolation technologies
Development of 32-bit+ precision converters
Standardization of wireless AFE modules for Industry 4.0