Overview
The 1.0SMBJ28A is a surface-mount TVS diode in the popular SMB package format. As part of the SMBJ series, it provides robust protection against transient voltage events including electrostatic discharge (ESD), electrical fast transients (EFT), and lightning-induced surges. The component's design allows it to respond to voltage spikes in picoseconds, clamping the voltage to safe levels before sensitive electronics can be damaged. Manufactured using silicon avalanche technology, the 1.0SMBJ28A offers reliable performance across industrial temperature ranges (-55°C to +150°C). Its compact SMB package (5.4mm × 3.6mm) makes it suitable for space-constrained applications while maintaining excellent thermal characteristics for power dissipation.
Structure and Working Principle
The 1.0SMBJ28A consists of a silicon PN junction designed to avalanche at precisely 28V. When the voltage across the diode exceeds this threshold, the device transitions from high-impedance to low-impedance state in less than 1 picosecond. This creates a low-resistance path that diverts the transient current away from protected components. Internally, the diode features a large junction area to handle high peak currents (up to 20.5A for an 8/20μs pulse). The construction includes passivation layers and metallization optimized for surface-mount assembly processes. The component is polarity-sensitive, with clear cathode marking for proper PCB orientation.
Key Features
With a peak pulse power rating of 600W (for 10/1000μs waveform), the 1.0SMBJ28A offers superior protection compared to many competing devices. Its low clamping ratio (Vc/Vbr typically 1.3) ensures protected circuits experience minimal overvoltage. The diode maintains extremely low leakage current (<1μA) during normal operation, preserving power efficiency. The RoHS-compliant device features lead-free plating and is compatible with standard reflow soldering processes. Its hermetically sealed construction provides excellent moisture resistance (per J-STD-020), making it suitable for harsh environments. The component's performance remains stable over thousands of surge events, ensuring long-term reliability.
Application Areas
Primary applications include protection of data lines in industrial automation systems (RS-485, CAN bus), telecommunication equipment (xDSL, T1/E1 interfaces), and automotive electronics (ECUs, infotainment systems). The 1.0SMBJ28A is particularly effective for safeguarding 24V DC power rails common in industrial control systems. In consumer electronics, the diode protects USB ports, HDMI interfaces, and power supply inputs in smart home devices. Medical equipment manufacturers utilize it for patient-connected device protection to meet IEC 60601-1-2 standards. The component also finds use in renewable energy systems for PV panel bypass and inverter protection.
Maintenance and Precautions
While TVS diodes require no routine maintenance, periodic inspection of PCB solder joints is recommended in high-vibration environments. Ensure the component's package isn't cracked or discolored, which may indicate previous overstress events. Thermal imaging during surge testing can verify proper heat dissipation. Design precautions include maintaining adequate clearance (≥0.5mm) between the TVS diode and other components. The PCB layout should provide low-inductance paths to ground, with trace lengths minimized. Avoid placing vias between the TVS diode and protected component, as these increase impedance during transient events.
B2B Procurement Guide
When sourcing 1.0SMBJ28A diodes, verify manufacturer certifications (ISO 9001, IATF 16949 for automotive) and request detailed test reports including UL recognition. For high-reliability applications, consider devices with additional screening (burn-in, 100% electrical testing). Packaging options range from tape-and-reel (standard 3000 pieces) to bulk trays for automated assembly. Lead times typically range from 4-8 weeks for standard products, though distributor stock is commonly available. Minimum order quantities vary by supplier, with some offering samples for evaluation. Pricing tiers generally begin at 10,000 unit quantities, with additional discounts for annual volume commitments above 100,000 units.
Related Manufacturers
- 主营：MPS、ST、TOREX、NUVOTON、TI、BORN、SLKOR、YANGJIE、UTC、ADI、Infineon、Micron、SAMSUNG、TDK、MICROCHIP