Interface - Filters

Interface - Filters - Active

Part Number	Description / PDF	Quantity
LTC1064-1CSW#PBF Analog Devices, Inc.	IC FILTER 20KHZ LOWPASS 16SOIC	39
MAX267AEWG+ Analog Devices, Inc.	BANDPASS FILTER	371
LTC1064-7CSW#TRPBF Analog Devices, Inc.	IC FILTER 100KHZ LINEAR 16SOIC	0
MAX296CWE Analog Devices, Inc.	SWITCHED CAPACITOR FILTER, 1 FUN	3743
ADA4424-6ARUZ-RL Analog Devices, Inc.	6-CHANNEL SD/ED/HD VIDEO FILTER	2500
LTC1064-2CN#PBF Analog Devices, Inc.	IC FILTER 140KHZ LOWPASS 14DIP	1
LTC1565-31CS8#PBF Analog Devices, Inc.	IC FILTER 650KHZ LINEAR PH 8SOIC	213
MAX263BCWI Analog Devices, Inc.	UNIVERSAL AND BANDPASS FILTER	17
MAX268BCNG Analog Devices, Inc.	UNIVERSAL BANDPASS FILTER	3473
LTC1068CG#TRPBF Analog Devices, Inc.	IC FILTER 50KHZ SWITCHED 28SSOP	0
LTC1564IG#PBF Analog Devices, Inc.	IC FILTR 150KHZ ANTIALIAS 16SSOP	0
LTC1067IGN#PBF Analog Devices, Inc.	IC FILTER 20KHZ SWITCHED 16SSOP	970
LTC1069-7CS8#TRPBF Analog Devices, Inc.	IC FILTER 200KHZ LINEAR PH 8SOIC	0
MAX7453CSA Analog Devices, Inc.	3-CH VIDEO RECONSTRUCTION FILTER	31105
LTC1060CN#PBF Analog Devices, Inc.	IC FILTER 30KHZ UNIV SWTCH 20DIP	202
LTC1061CSW#TRPBF Analog Devices, Inc.	IC FILTER 35KHZ SWITCHED 20SOIC	0
MAX292CSA-G095 Analog Devices, Inc.	LOWPASS SWTCHED-CAPACITOR FILTER	0
MAX7432AEUD+ Analog Devices, Inc.	SD VIDEO RECONSTRUCTION FILTER	28901
HMC897LP4ETR Analog Devices, Inc.	IC FILTER BAND PASS 24SMT	0
HMC895 Analog Devices, Inc.	IC FILTER BAND PASS 24SMT	0

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

Type	Functional Characteristics	Application Examples
Low-Pass Filter (LPF)	Attenuates frequencies above cutoff; smooths signals	Audio DAC output filtering, ECG signal processing
High-Pass Filter (HPF)	Blocks DC components and low-frequency noise	Speaker crossover networks, AC coupling circuits
Band-Pass Filter (BPF)	Allows frequencies within a specific range	Wireless receiver front-ends, spectral analysis
Band-Reject Filter (BRF)	Attenuates a specific frequency band	Power line noise cancellation (50/60Hz), RFID systems
All-Pass Filter	Phase shifting without amplitude modification	Phase 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

Parameter	Description	Importance
Cutoff Frequency (f_c)	Frequency at -3dB point	Determines passband boundary
Voltage Gain (A_v)	Amplification factor	Signal strength adjustment
Quality Factor (Q)	Selectivity of frequency response	Controls transition band steepness
Input/Output Impedance	Matching with external circuits	Minimizes signal reflection
Power Supply Rejection Ratio (PSRR)	Noise immunity from power rails	Improves 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

Manufacturer	Representative Products	Key Features
Texas Instruments	LMV721, PGA2500	Rail-to-rail output, programmable gain
Analog Devices	LTC1564, MAX275	Low-power operation, tunable cutoff
STMicroelectronics	TS272, LMC662	CMOS technology, high precision
NXP Semiconductors	SAF7741, TDA7409	Audio-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