Analog Front-End (AFE)
Definition: An Analog Front-End (AFE) is a circuit block that interfaces between analog sensors or signals and digital processing systems (e.g., ADCs, microcontrollers). It conditions the analog signal through amplification, filtering, level-shifting, and sometimes excitation drive.
Key Functions:
- Amplification – Increases small sensor signals (e.g., mV) to match ADC input range.
- Filtering – Removes noise using low-pass, high-pass, or band-pass filters.
- Signal Conditioning – Includes offset correction, gain adjustment, and impedance matching.
- Excitation – Provides voltage/current sources for sensors (e.g., RTDs, bridge sensors).
- ADC Interface – Drives the analog-to-digital converter with optimized signal levels.
Common Applications:
Biomedical ECG/EEG systems
Industrial Pressure/temperature sensors
Automotive Oxygen sensors, position sensing
Consumer Wearables, touch sensing
Typical Components:
Instrumentation Amplifier
Programmable Gain Amplifier (PGA)
Low-Pass Filter (LPF)
Voltage Reference
ADC Driver
Note: Integrated AFEs (e.g., TI ADS129x, ADI ADAS1000) combine multiple functions in a single chip for precision sensing.