Interface - Filters - Active

Image Part Number Description / PDF Quantity Rfq
MAX7423EUA+T

MAX7423EUA+T

Maxim Integrated

IC FILTER 45KHZ LOWPASS 8UMAX

0

MAX7490CEE+

MAX7490CEE+

Maxim Integrated

IC FILTER 40KHZ SWITCHED 16QSOP

107900

MAX297ESA+

MAX297ESA+

Maxim Integrated

IC FILTER 25KHZ LOWPASS 8SOIC

1894700

MAX7420EUA+

MAX7420EUA+

Maxim Integrated

IC FILTER 45KHZ BUTTER 8UMAX

1050

LTC1064-4CN#PBF

LTC1064-4CN#PBF

Analog Devices, Inc.

IC FILTER 100KHZ LOWPASS 14DIP

0

MAX297EPA

MAX297EPA

Analog Devices, Inc.

LOWPASS SWTCHED-CAPACITOR FILTER

1338

LTC1064-7CN#PBF

LTC1064-7CN#PBF

Analog Devices, Inc.

IC FILTER 100KHZ LINEAR PH 14DIP

0

LTC6601IUF-1#TRPBF

LTC6601IUF-1#TRPBF

Analog Devices, Inc.

IC FILTER 28MHZ 20QFN

0

MAX7414EUA+

MAX7414EUA+

Maxim Integrated

IC FILTER 15KHZ BUTTER 8UMAX

0

LT1567IMS8#PBF

LT1567IMS8#PBF

Analog Devices, Inc.

IC FILTER 5MHZ ANTIALIASNG 8MSOP

0

LTC6602CUF#TRPBF

LTC6602CUF#TRPBF

Analog Devices, Inc.

IC FILTER 300KHZ BAND PASS 24QFN

0

MAX281AEPA+

MAX281AEPA+

Maxim Integrated

IC FILTER 20KHZ LOWPASS 8DIP

800

LTC6605CDJC-10#TRPBF

LTC6605CDJC-10#TRPBF

Analog Devices, Inc.

DUAL MATCHED 10MHZ FILTER WITH L

2500

LTC1067-50CGN#TRPBF

LTC1067-50CGN#TRPBF

Analog Devices, Inc.

IC FILTER 40KHZ SWITCHED 16SSOP

0

MAX295CSA+

MAX295CSA+

Maxim Integrated

IC FILTER 50KHZ BUTTER 8SOIC

107

MAX7407ESA+T

MAX7407ESA+T

Maxim Integrated

IC FILTER 10KHZ LOWPASS 8SOIC

0

LTC1061CN#PBF

LTC1061CN#PBF

Analog Devices, Inc.

IC FILTER 35KHZ UNIV SWTCH 20DIP

0

LTC1067CS#PBF

LTC1067CS#PBF

Analog Devices, Inc.

IC FILTER 20KHZ SWITCHED 16SOIC

299

LTC1067-50CGN#PBF

LTC1067-50CGN#PBF

Analog Devices, Inc.

IC FILTER 40KHZ SWITCHED 16SSOP

75

MAX7420EUA+T

MAX7420EUA+T

Maxim Integrated

IC FILTER 45KHZ BUTTER 8UMAX

5000

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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