SMD1812-301 Alternative / Equivalent / Replacement

YINT Electronics — Gas Discharge Tube (GDT)

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1. Introduction

The SMD1812-301 is a 300V surface-mount gas discharge tube (GDT) in the 1812 package that protects data, signal, and control lines from lightning-induced overvoltage. It has a DC breakdown voltage of 300V ±20% and handles 2.0kA impulse discharge current per 8/20µs waveform. This GDT works in telecom base stations, broadband access equipment, industrial control interfaces, and outdoor security systems where signal integrity and surge immunity are critical. The ultra-low capacitance of 0.5pF preserves signal quality on high-speed data lines without adding insertion loss.

The SMD1812-301 is an industry standard part number in the 1812 SMD GDT format, compatible across major GDT manufacturers. YINT Electronics manufactures this model as a fully compatible replacement in the SMD1812 surface-mount package. The device delivers a fast impulse spark-over voltage of 300V (1kV/µs) for quick protection against fast-rising transient events. YINT's SMD1812-301 benefits from 100% breakdown voltage testing on every device, ensuring consistent firing characteristics across every production lot.

Engineers searching for an SMD1812-301 replacement or an SMD1812-301 equivalent can specify the YINT SMD1812-301 as a direct drop-in substitute. It offers a tight DC breakdown voltage tolerance and stable firing characteristics over its entire rated life of thousands of surge events. The compact 1812 footprint measures just 4.5mm x 3.2mm with a low profile of 2.7mm, fitting easily into dense PCB layouts. Whether you need an SMD1812-301 substitute for an existing BOM or a second-source GDT for new designs, YINT provides a reliable supply with competitive lead times.

2. Product Overview

The SMD1812 series is a popular family of surface-mount gas discharge tubes covering breakdown voltages from 71V to 601V in the compact 1812 package (4.5mm x 3.2mm). Each part delivers 2.0kA impulse discharge current for a broad range of surge protection applications from low-voltage telecom lines to higher-voltage power interfaces. The SMD package provides automated SMT assembly compatibility, making it suitable for high-volume production where through-hole GDTs like the 3R series are too large for modern PCB designs.

The SMD1812-301 is optimized for protecting 300V-rated telecom and signal lines commonly found in base station antenna interfaces, POE outdoor equipment, industrial Ethernet ports, and security camera video transmission lines. Its 300V DC breakdown voltage allows it to sit across a 300V signal line without conducting under normal operating conditions. When a lightning surge or power cross event occurs, the gas inside the tube ionizes and provides a low-impedance path to ground, clamping the overvoltage to a safe level. The GDT resets automatically after the surge subsides, ready for the next event.

YINT produces the full SMD1812 series from SMD1812-071 (71V) through SMD1812-601 (601V). This complete voltage coverage lets customers source all 1812 GDT protection needs from one manufacturing partner, simplifying supply chain management and reducing qualification costs. The SMD1812-301 uses ceramic sealed gas discharge technology with stable firing characteristics over its full rated life of thousands of surge events. The device maintains its specified DC breakdown voltage within ±20% tolerance from -40°C to +90°C for consistent protection in outdoor installations.

3. Key Features

• DC Breakdown Voltage: 300V — ±20% tolerance for consistent firing
• Impulse Spark-over: 300V — 1kV/µs waveform, fast transient response
• Impulse Discharge Current: 2.0kA — 8/20µs, 10 hits, robust surge handling
• Ultra-low Capacitance: 0.5pF — Preserves signal integrity on data lines
• SMD1812 Package — Compact 4.5mm x 3.2mm surface-mount footprint
• High Insulation Resistance — Low leakage under normal operating conditions
• Wide Temperature Range — -40°C to +90°C for outdoor use
• RoHS Compliant — Lead-free and environmentally friendly

4. Specifications

5. Cross Reference

The SMD1812-301 is a standard GDT part number used across the industry. YINT's SMD1812-301 is a direct drop-in replacement with identical package dimensions and electrical characteristics, ensuring compatibility without redesign.

6. Comparison with Similar Models

Engineers often compare the SMD1812-301 with nearby voltage variants and alternative package GDTs. The table below shows key differences to help select the right GDT for each design.

The SMD1812-301 provides the best balance of breakdown voltage, surge current, and package size for 300V-rated signal line protection. For lower voltage protection, the SMD1812-231 (230V) covers 230V-rated circuits. For higher voltage protection, the SMD1812-471 (470V) covers 470V DC bus and ring voltage applications. All SMD1812 series variants share the same package footprint, making them drop-in replacements across the voltage range.

For designs that need higher surge current capacity, the CG300 (5kA) and 3R470L (10kA) provide more surge handling but require larger PCB footprints. The SMD1812-301 is the recommended choice for space-constrained designs where 2.0kA surge capacity is sufficient for secondary protection levels.

7. Applications

• Telecom base station antenna interface lightning protection
• Broadband and CATV equipment surge suppression
• Industrial Ethernet port primary protection
• Security camera video and power line lightning protection
• POE outdoor equipment overvoltage clamping
• Data communication signal line primary protection
• Outdoor LED lighting control interface surge suppression
• Access control and intercom system lightning protection
• Traffic monitoring equipment communication line protection
• Solar inverter and battery management communication interface
• Smart grid and utility metering data port protection
• Railway signaling and trackside equipment surge protection

8. Why Choose YINT

• 19+ years of manufacturing expertise in circuit protection and power semiconductors since 2006
• 40+ patents and certifications with robust process control per ITU-T and IEC standards
• Global sales network serving North America, Europe, Asia, and Latin America
• Full SMD1812 series from 71V to 601V for one-stop GDT sourcing across all voltage ratings
• Direct OEM replacement — pin-to-pin compatible with SMD1812-301 from all major brands
• Engineering team available for application assistance and cross-reference verification
• Free samples for testing and qualification upon request with fast turnaround
• Direct manufacturer pricing with volume discounts available
• Short lead times with active production status
• All devices fully RoHS compliant with lead-free manufacturing

9. Ordering Information

10. FAQ

Q1: Is YINT SMD1812-301 a direct replacement for Bourns or Littelfuse SMD1812-301?
A: Yes. The YINT SMD1812-301 has identical electrical specs and 1812 package dimensions. It drops in without any PCB redesign.

Q2: What is the difference between SMD1812-301 and SMD1206-301?
A: SMD1812-301 is in the larger 1812 package (4.5mm x 3.2mm), while the SMD1206 series uses the smaller 1206 package with reduced surge current capacity.

Q3: What is the impulse discharge current rating?
A: 2.0kA for 8/20µs waveform, 10 hits. Suitable for secondary lightning protection in telecom and industrial applications.

Q4: Can SMD1812-301 be used for AC mains protection?
A: No. GDTs are typically used for signal and communication line protection. For AC mains, use varistors or SPDs.

Q5: What is the capacitance of SMD1812-301?
A: 0.5pF at 1MHz, providing minimal signal degradation on high-speed data lines.

Q6: How does SMD1812-301 compare with CG300?
A: Both are 300V GDTs. SMD1812-301 has 2.0kA surge rating and 0.5pF capacitance in a smaller footprint. CG300 has 5.0kA surge rating and 1.0pF capacitance in a larger package. Choose based on your surge current needs and available PCB space.

Q7: What is the operating temperature range?
A: -40°C to +90°C, suitable for outdoor telecom and industrial installations.

Q8: Does YINT provide free samples for testing?
A: Yes. Contact YINT with your project details for sample requests and qualification support.

11. Conclusion

YINT Electronics' SMD1812-301 is a reliable, compact GDT replacement for industry-standard 300V surface-mount gas discharge tubes. It delivers 2.0kA surge handling, ultra-low 0.5pF capacitance, and fast spark-over response in a space-saving 1812 package for telecom, industrial, and outdoor signal line protection.

Contact YINT Electronics at global@yint.com.cn for datasheets, samples, or pricing. Our engineering team is ready to assist with cross-references and application support.