Interface - Signal Terminators

Part Number	Description / PDF	Quantity
UCC5687PM Texas Instruments	SCSI TERMINATOR, 27-LINE, 105OHM	9600
UCC5696PN Texas Instruments	SCSI TERMINATOR, 27-LINE, 105OHM	1904
UCC5642MWP Texas Instruments	SCSI TERMINATOR, 9-LINE, 105OHM	27643
UCC5632MWP Texas Instruments	MULTI-MODE SCSI 9 LINE TERMINAT	870
UCC5640PW24TR Texas Instruments	UCC5640 9 LINE 2.7-5V LVD TERMIN	100000
UCC5672PWPTR Texas Instruments	UCC5672 9 LINE 2.7-5V MULTIMODE	22865
UCC5686PMG4 Texas Instruments	SCSI TERMINATOR, 27-LINE, 105OHM	149
UC5603QPTR Texas Instruments	SCSI TERMINATOR, 9-LINE, 110OHM	2250
UC560DP Texas Instruments	TERMINATOR SUPPORT CIRCUIT	55639
UCC5606PWPTR Texas Instruments	IC SCSI 9-LINE TERM 24TSSOP	1822
UCC5614DPTR Texas Instruments	SCSI TERMINATOR, 9-LINE, 110OHM	0
UCC5640PW28 Texas Instruments	SCSI TERMINATOR, 9-LINE, 105OHM	12165
TL2218-285PW Texas Instruments	TL2218-285 CURRENT-MODE SCSI TER	0
UCC5618PWPTR Texas Instruments	SCSI TERMINATOR, 18-LINE, 110OHM	19615
UCC5630AMWP Texas Instruments	SCSI TERMINATOR, 9-LINE, 105OHM	8229
UC5603DPTR Texas Instruments	SCSI TERMINATOR, 9-LINE, 110OHM	21525
UCC5620MWP Texas Instruments	SCSI TERMINATOR, 27-LINE, 110OHM	23395
UC5601N Texas Instruments	SCSI TERMINATOR, 18-LINE, 110OHM	6195
UCC5696PNR Texas Instruments	SCSI TERMINATOR, 27-LINE, 105OHM	1000
UCC5617DWPTR Texas Instruments	SCSI TERMINATOR, 18-LINE, 110OHM	64000

Interface - Signal Terminators

1. Overview

Signal terminators are specialized integrated circuits designed to match impedances and suppress signal reflections in high-speed transmission lines. They play a critical role in maintaining signal integrity by ensuring that voltage and current signals propagate without distortion. These devices are essential in modern electronics, particularly in applications requiring high-frequency data transmission, such as telecommunications, computing, and industrial automation.

2. Main Types and Functional Classification

Type	Functional Characteristics	Application Examples
Resistive Terminators	Fixed or adjustable resistors to match transmission line impedance	DDR memory interfaces, RS-485 buses
Capacitive Terminators	Block DC signals while allowing AC signals to pass	High-speed ADC/DAC interfaces
Active Terminators	Dynamic impedance adjustment with voltage regulation	Fiber optic communication systems
Differential Terminators	Balanced termination for differential signaling	Ethernet (10GBASE-T), USB 3.0

3. Structure and Composition

Signal terminators typically consist of: - Precision resistors/capacitors embedded in silicon or ceramic substrates. - Package housing (e.g., SMT, TSSOP) with thermal dissipation features. - Internal ESD protection layers to prevent voltage spikes. - Multi-layer metallization for high-frequency signal routing.

4. Key Technical Specifications

Parameter	Description
Termination Resistance ( )	Matches transmission line impedance (e.g., 50 , 75 , 100 ).
Frequency Range (GHz)	Determines suitability for high-speed applications (e.g., 0.1-10 GHz).
Power Handling (W)	Maximum power dissipation without thermal degradation.
Capacitance (pF)	Affects signal rise/fall time in capacitive terminators.
Impedance Tolerance (%)	Accuracy of impedance matching (e.g., 2%, 5%).

5. Application Fields

Telecommunications: 5G base stations, optical transceivers.
Computing: Motherboard PCIe interfaces, GPU memory buses.
Industrial: PLCs, motor drive signal lines.
Automotive: CAN FD bus systems, ADAS sensors.

Case Study: In 10GBASE-T Ethernet, differential terminators ensure 100 impedance matching to reduce crosstalk and bit error rates.

6. Leading Manufacturers and Products

Manufacturer	Representative Product	Key Features
TI (Texas Instruments)	SN75LBC176	RS-485 line driver with integrated termination
Analog Devices	ADN4661	Low-power LVDS signal terminator
Infineon Technologies	TLE5012B	Automotive CAN FD controller with termination
STMicroelectronics	TS922	Rail-to-rail op-amp for active termination circuits

7. Selection Guidelines

Key considerations: 1. Impedance match: Align with transmission line characteristics. 2. Frequency compatibility: Ensure specifications exceed system requirements. 3. Environmental factors: Temperature range, vibration resistance. 4. Package size: Prioritize SMT for high-density PCBs.
Case Study: For aerospace applications, select terminators with 2% impedance tolerance and -55 C to +125 C operating range.

8. Industry Trends

Development of terahertz-range terminators for 6G networks.
Integration with AI-driven impedance tuning in active terminators.
Adoption of nanomaterial-based substrates for improved thermal management.
Growth in automotive Ethernet terminators due to vehicle electrification.