Microchip Technology 1N5355/TR12

Overview

1N5355/TR12 from Microsemi is a 5 W, 18 V ±5% axial-leaded silicon Zener diode designed for precision voltage regulation in power supply feedback loops, overvoltage protection circuits, and reference voltage generation. It delivers stable regulation across 10 mA to 65 mA operating current, with 2.5 Ω dynamic impedance at 65 mA and 264 Ω knee impedance at 1 mA, suitable for industrial power converters requiring robust thermal performance up to +150°C.

For engineers reviewing the 1N5355/TR12 datasheet, 1N5355/TR12 pinout, 1N5355/TR12 application, or 1N5355/TR12 equivalent, key selection criteria include its 18 V nominal Zener voltage, ±5% tolerance (B suffix), 5.5 V maximum voltage regulation (ΔVZ), and compatibility with tape-and-reel automated assembly (TR12 suffix).

Technical Context

This device operates as a two-terminal voltage reference, maintaining regulation by conducting reverse current above its specified breakdown threshold. Its low 25 °C/W junction-to-lead thermal resistance enables full 5 W dissipation when leads are mounted at 3/8" (10 mm) from body, while its 85 °C/W junction-to-ambient rating applies to FR4 PCB mounting with defined copper pad geometry.

The 1N5355/TR12 exhibits minimal voltage drift versus current-ΔVZ = 5.5 V between 10% and 50% of IZM-and withstands non-repetitive 8.3 ms half-sine surge currents up to 75 A, supporting transient suppression in DC power rails without external clamping components.

Key Specifications

Pinout & Package

Package: Axial-leaded T-18 plastic case (Void-free UL94V-0 epoxy), cathode indicated by band; RoHS-compliant matte-tin plating per MIL-STD-750 Method 2026.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar Zener regulation applications.

Compared with 1N5355B and MMBZ5245B, the 1N5355/TR12 uniquely combines JEDEC-standard axial form factor, full 5 W dissipation capability, and TR12 tape-and-reel readiness-making it the only option for high-reliability, high-power, automated production of industrial power supplies.

Availability

1N5355/TR12 is available at Aetrix Electronics and suitable for industrial power supplies, overvoltage protection circuits, and precision reference designs requiring stable component supply with traceable sourcing and long-term lifecycle support.

Supply support for 1N5355/TR12 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Microsemi (now part of Microchip Technology) is a U.S.-based semiconductor company specializing in high-reliability analog and mixed-signal components for aerospace, defense, and industrial markets.

The 1N53xxB series was engineered for ruggedized voltage regulation in mission-critical power systems-emphasizing thermal resilience, surge immunity, and JEDEC-standard interchangeability across military and commercial applications.

FAQ

What is the Zener voltage tolerance of the 1N5355/TR12?

The 1N5355/TR12 has a ±5% Zener voltage tolerance, confirmed by its "B" suffix per Microsemi's documentation. This means its regulated voltage falls within 17.1 V to 18.9 V at 65 mA test current and 25°C lead temperature. The 1N5355/TR12 maintains this tolerance across its full operating temperature range of –65°C to +150°C, making it suitable for applications where stable reference accuracy is critical despite thermal variation.

Does the 1N5355/TR12 require derating at elevated temperatures?

Yes, the 1N5355/TR12 must be derated linearly above 25°C lead temperature: power dissipation decreases by 20 mW/°C beyond that point, per Figure 1 in the Microsemi datasheet. At 100°C lead temperature, its usable power drops to 3.5 W. For PCB-mounted operation, derating follows the 85°C/W junction-to-ambient curve, limiting steady-state power to 1.47 W at 25°C ambient unless enhanced copper thermal pads are used.

What does the "TR12" suffix indicate for the 1N5355/TR12?

The "TR12" suffix on the 1N5355/TR12 denotes EIA-296 compliant tape-and-reel packaging with 12 mm carrier tape width, enabling direct use in automated pick-and-place equipment. This configuration contains 1,000 units per reel and meets standard moisture sensitivity Level 1 requirements-no dry pack or baking is needed before assembly. The 1N5355/TR12 retains identical electrical and thermal specifications as the bulk 1N5355B variant.

Can the 1N5355/TR12 replace older 1N5355 versions without design changes?

Yes-the 1N5355/TR12 is a direct replacement for legacy 1N5355 devices with identical electrical characteristics, mechanical dimensions, and thermal performance. Its "B" suffix confirms ±5% tolerance matching historical 1N5355B variants, and the TR12 packaging adds automation compatibility without altering circuit behavior. No PCB layout or schematic modifications are required when upgrading to the 1N5355/TR12.

What is the maximum surge current rating for the 1N5355/TR12?

The 1N5355/TR12 is rated for a non-repetitive peak surge current (I_ZSM) of 75 A, defined as the maximum amplitude of an 8.3 ms half-sine waveform. This rating is validated under specified test conditions and supports standalone transient suppression in 15–24 V DC systems. Engineers must ensure external series impedance limits average power dissipation during repeated surges to avoid exceeding the 5 W steady-state limit of the 1N5355/TR12.