Interface - Filters - Active

Image Part Number Description / PDF Quantity Rfq
MAX7422EUA+T

MAX7422EUA+T

Maxim Integrated

IC FILTER 45KHZ LOWPASS 8UMAX

0

MAX267BENG+

MAX267BENG+

Maxim Integrated

IC FILTER 57KHZ BAND PASS 24DIP

416750

MAX7400ESA+T

MAX7400ESA+T

Maxim Integrated

IC FILTER 10KHZ LOWPASS 8SOIC

1286

MAX7411EUA+T

MAX7411EUA+T

Maxim Integrated

IC FILTER 15KHZ LOWPASS 8UMAX

7500

MAX7408CUA+

MAX7408CUA+

Maxim Integrated

IC FILTER 15KHZ LOWPASS 8UMAX

1829150

MAX291ESA+T

MAX291ESA+T

Maxim Integrated

IC FILTER 25KHZ BUTTER 8SOIC

22500

MAX275AEPP+

MAX275AEPP+

Maxim Integrated

IC FILTER 300KHZ LOWPASS 20DIP

91224

MAX7424CUA+

MAX7424CUA+

Maxim Integrated

IC FILTER 45KHZ BUTTER 8UMAX

792450

MAX275BCPP+

MAX275BCPP+

Maxim Integrated

IC FILTER 300KHZ LOWPASS 20DIP

441378

MAX7420CUA+

MAX7420CUA+

Maxim Integrated

IC FILTER 45KHZ BUTTER 8UMAX

37250

MAX7491EEE+T

MAX7491EEE+T

Maxim Integrated

IC FILTER 40KHZ SWITCHED 16QSOP

0

MAX7412EUA+T

MAX7412EUA+T

Maxim Integrated

IC FILTER 15KHZ LOWPASS 8UMAX

5000

MAX292ESA+T

MAX292ESA+T

Maxim Integrated

IC FILTER 25KHZ LOWPASS 8SOIC

2500

MAX7421CUA+

MAX7421CUA+

Maxim Integrated

IC FILTER 45KHZ LOWPASS 8UMAX

1331750

MAX7426CUA+T

MAX7426CUA+T

Maxim Integrated

IC FILTER 12KHZ LOWPASS 8UMAX

0

MAX7419EUA+

MAX7419EUA+

Maxim Integrated

IC FILTER 45KHZ LOWPASS 8UMAX

552100

MAX7421EUA+

MAX7421EUA+

Maxim Integrated

IC FILTER 45KHZ LOWPASS 8UMAX

100300

MAX294EPA+

MAX294EPA+

Maxim Integrated

IC FILTER 25KHZ LOWPASS 8DIP

500

MAX267BCWG+T

MAX267BCWG+T

Maxim Integrated

IC FILTER 57KHZ BAND PASS 24SOIC

0

MAX7401CPA+

MAX7401CPA+

Maxim Integrated

IC FILTER 5KHZ BESSEL LOW P 8DIP

847200

Interface - Filters - Active

1. Overview

Active filters are electronic integrated circuits (ICs) that use active components (e.g., operational amplifiers) combined with passive elements (resistors, capacitors) to selectively attenuate or amplify specific frequency ranges. Unlike passive filters, active filters can provide gain, high input impedance, and low output impedance. They are critical in modern electronics for signal conditioning, noise suppression, and frequency domain processing in communication systems, audio equipment, and industrial control systems.

2. Main Types and Functional Classification

TypeFunctional CharacteristicsApplication Examples
Low-Pass Filter (LPF)Attenuates frequencies above cutoff; smooths signalsAudio DAC output filtering, ECG signal processing
High-Pass Filter (HPF)Blocks DC components and low-frequency noiseSpeaker crossover networks, AC coupling circuits
Band-Pass Filter (BPF)Allows frequencies within a specific rangeWireless receiver front-ends, spectral analysis
Band-Reject Filter (BRF)Attenuates a specific frequency bandPower line noise cancellation (50/60Hz), RFID systems
All-Pass FilterPhase shifting without amplitude modificationPhase equalization in data transmission, delay equalizers

3. Structure and Components

Active filters typically consist of:
- Operational Amplifiers (Op-Amps): Provide gain and buffering.
- RC Networks: Define frequency response through resistor-capacitor combinations.
- Feedback Circuits: Stabilize performance and control Q-factor.
- Power Supply Pins: For biasing active components.
Modern IC implementations integrate these elements in monolithic packages, such as 8-pin SOIC or TSSOP, with laser-trimmed precision components.

4. Key Technical Specifications

ParameterDescriptionImportance
Cutoff Frequency (fc)Frequency at -3dB pointDetermines passband boundary
Voltage Gain (Av)Amplification factorSignal strength adjustment
Quality Factor (Q)Selectivity of frequency responseControls transition band steepness
Input/Output ImpedanceMatching with external circuitsMinimizes signal reflection
Power Supply Rejection Ratio (PSRR)Noise immunity from power railsImproves signal integrity

5. Application Areas

  • Telecommunications: DSL line drivers, 5G transceivers
  • Consumer Electronics: Equalizers in smartphones, noise-canceling headphones
  • Industrial: Sensor signal conditioning in PLCs
  • Medical Devices: Biopotential amplifiers for EMG/EKG
  • Automotive: Radar signal processing in ADAS

6. Leading Manufacturers and Products

ManufacturerRepresentative ProductsKey Features
Texas InstrumentsLMV721, PGA2500Rail-to-rail output, programmable gain
Analog DevicesLTC1564, MAX275Low-power operation, tunable cutoff
STMicroelectronicsTS272, LMC662CMOS technology, high precision
NXP SemiconductorsSAF7741, TDA7409Audio-specific filtering with DSP integration

7. Selection Guidelines

Key considerations include:
- Required frequency range and stability over temperature
- Power consumption constraints (e.g., portable devices)
- Package size for space-constrained applications
- Component tolerance and aging effects
- Cost vs. performance trade-offs (e.g., using switched-capacitor filters for adjustable cutoff)

8. Industry Trends

Future developments focus on:
- Higher integration with ADC/DACs and DSP cores
- Miniaturization via 3D packaging and MEMS technology
- Adaptive filters using AI-driven parameter optimization
- Enhanced radiation hardness for automotive/aerospace applications
- Energy-efficient designs for IoT edge devices

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