Interface - Filters

Interface - Filters - Active

Part Number	Description / PDF	Quantity
LTC1064-4CSW#TRPBF Analog Devices, Inc.	IC FILTER 100KHZ LOWPASS 16SOIC	0
ADMV8432ACPZ-R5 Analog Devices, Inc.	16 TO 32 GHZ TUNABLE BPF	0
MAX271CWG Analog Devices, Inc.	CONTINUOUS LOWPASS FILTER	71
LTC1563-3IGN#TRPBF Analog Devices, Inc.	IC FILTER 256KHZ LOWPASS 16SSOP	0
MAX267AENG Analog Devices, Inc.	BANDPASS FILTER	0
MAX7414CPA+ Analog Devices, Inc.	SWITCHED CAPACITOR FILTER, 1 FUN	3931
LTC1565-31IS8#PBF Analog Devices, Inc.	IC FILTER 650KHZ LINEAR PH 8SOIC	275
MAX267BCWG Analog Devices, Inc.	BANDPASS FILTER	0
LTC6602CUF#PBF Analog Devices, Inc.	IC FILTER 300KHZ BAND PASS 24QFN	106
LTC1059CS#PBF Analog Devices, Inc.	IC FILTER 40KHZ SWITCHED 14SOIC	0
LTC1068-200CG#TRPBF Analog Devices, Inc.	IC FILTER 25KHZ SWITCHED 28SSOP	0
LTC1067IGN#TRPBF Analog Devices, Inc.	IC FILTER 20KHZ SWITCHED 16SSOP	0
LTC1566-1IS8#PBF Analog Devices, Inc.	IC FILTER 2.3MHZ LOW PASS 8SOIC	185
LTC1164CSW#PBF Analog Devices, Inc.	IC FILTER 20KHZ SWITCHED 24SOIC	0
MAX292CSA Analog Devices, Inc.	LOWPASS SWTCHED-CAPACITOR FILTER	0
LT1567CMS8#PBF Analog Devices, Inc.	IC FILTER 5MHZ ANTIALIASNG 8MSOP	793
LTC1562IG#PBF Analog Devices, Inc.	IC FILTER 150KHZ UNIV 20SSOP	1
LTC1563-2IGN#PBF Analog Devices, Inc.	IC FILTER 256KHZ LOWPASS 16SSOP	1979
MAX9586AZK+ Analog Devices, Inc.	MAX9586 VIDEO FILTER AMPLIFIER	31471
MAX260ACNG+ Analog Devices, Inc.	MAX260 MICROPROCESSOR PROGRAMMAB	161

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