Microchip Technology 1N5353B/TR12

Overview

1N5353B/TR12 from Microsemi is a 5 W axial-leaded silicon Zener diode with nominal regulation voltage of 16 V, ±5% tolerance (B suffix), 2.5 Ω maximum dynamic impedance at 75 mA test current, and 75 mA maximum regulator current when adequately heat-sunk. It operates from –65 °C to +150 °C and is used for precision voltage reference and overvoltage protection in power supply feedback loops.

For engineers reviewing the 1N5353B/TR12 datasheet, 1N5353B/TR12 pinout, 1N5353B/TR12 application, or 1N5353B/TR12 equivalent, key selection criteria include Zener voltage accuracy, thermal resistance (25 °C/W junction-to-lead), surge current rating (6.0 A), voltage regulation (ΔVZ = 0.30 V), and RoHS-compliant matte-tin plating per MIL-STD-750.

Technical Context

This discrete Zener diode functions as a two-terminal voltage reference device operating in reverse breakdown. Its regulation performance is defined at 75 mA test current (IZT), with dynamic impedance measured using 1 kHz AC modulation at 10% of IZT, and voltage regulation (ΔVZ) specified as the difference between voltages at 10% and 50% of IZM.

The device features a void-free thermosetting epoxy T-18 package rated for 5 W steady-state dissipation at 25 °C lead temperature, derating linearly above that point. Thermal resistance is 25 °C/W junction-to-lead (3/8″ lead length) and 85 °C/W junction-to-ambient on FR4 with defined copper pad geometry.

Key Specifications

Pinout & Package

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

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N5353B/TR12, the bulk version offers identical regulation but lacks tape-and-reel convenience, while MMBZ5245BS-7-F trades power handling and thermal robustness for miniaturization-making 1N5353B/TR12 optimal for industrial power rail stabilization where heat and surge resilience matter.

Availability

1N5353B/TR12 is available at Aetrix Electronics and suitable for switch-mode power supplies, overvoltage clamping circuits, programmable voltage references, and industrial sensor excitation requiring stable component supply and long-term obsolescence management.

Supply support for 1N5353B/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 designed for ruggedized voltage regulation in harsh-environment power systems, emphasizing thermal stability, surge survivability, and JEDEC-standardized manufacturability.

FAQ

What is the Zener voltage tolerance of the 1N5353B/TR12?

The 1N5353B/TR12 has a Zener voltage tolerance of ±5%, as indicated by the "B" suffix per Microsemi's documentation. This means its measured V_Z falls between 15.2 V and 16.8 V at 75 mA test current and 25 °C lead temperature. The tolerance is guaranteed across the full operating temperature range of –65 °C to +150 °C, and applies specifically to the 1N5353B/TR12-not to other suffix variants like A (±10%) or C (±2%).

Does the 1N5353B/TR12 require a heatsink for 5 W operation?

Yes-the 1N5353B/TR12 requires adequate heat sinking to sustain 5 W continuous dissipation. Its thermal resistance is 25 °C/W junction-to-lead at 3/8″ (10 mm) lead length from the body. Without this lead length or supplemental heatsinking, power must be derated per Figure 1 in the datasheet. On FR4 PCBs with standard copper pads, its junction-to-ambient thermal resistance rises to 85 °C/W, limiting usable power to ~1.47 W at 25 °C ambient.

What does the "TR12" suffix mean in 1N5353B/TR12?

The "TR12" suffix indicates tape-and-reel packaging per EIA-296 standard, with 12 mm tape width. It does not affect electrical or thermal specifications-1N5353B/TR12 is functionally identical to bulk 1N5353B. The TR12 format enables automated surface-mount placement equipment compatibility, supporting high-volume manufacturing. The "e3" RoHS designation is also included in the full part marking per Microsemi's revision D datasheet.

Can the 1N5353B/TR12 be used in place of a 1N4745A?

No-the 1N5353B/TR12 is not a direct substitute for the 1N4745A. While both are 16 V Zeners, the 1N4745A is a 1 W device with ±5% tolerance and higher dynamic impedance (~17 Ω). The 1N5353B/TR12 delivers 5× the power (5 W), lower Z_Z (2.5 Ω), and different thermal characteristics. Substituting it into a 1 W design risks excessive self-heating and board-level thermal stress unless layout and heatsinking are requalified.

Is the 1N5353B/TR12 compliant with RoHS and REACH regulations?

Yes-the 1N5353B/TR12 is RoHS-compliant, as confirmed by the "e3" suffix in its full manufacturer designation (1N5353B/TR12 e3). It uses RoHS-compliant matte-tin plating on leads per MIL-STD-750 Method 2026 and void-free UL94V-0 epoxy encapsulation. Microsemi's datasheet explicitly states RoHS compliance for all e3-suffixed 1N53xxB devices, including 1N5353B/TR12, with full REACH SVHC screening performed per regulatory requirements.