Microchip Technology 1N5373BE3/TR12

Overview

1N5373BE3/TR12 from Microsemi is a 5 W axial-leaded silicon Zener diode with nominal regulation voltage of 68 V, ±5% tolerance (B suffix), 20 mA test current (IZT), 44 Ω dynamic impedance (ZZ), and 500 mA maximum Zener current (IZM) when adequately heat-sunk. It operates across –65 °C to +150 °C and is used for precision voltage reference and overvoltage protection in industrial power supplies.

For engineers reviewing the 1N5373BE3/TR12 datasheet, 1N5373BE3/TR12 pinout, 1N5373BE3/TR12 application, or 1N5373BE3/TR12 equivalent, key selection criteria include Zener voltage accuracy, thermal resistance (25 °C/W junction-to-lead), surge current rating (500 A), reverse leakage (<0.5 µA at 51.7 V), and RoHS-compliant matte-tin plating per MIL-STD-750.

Technical Context

This device functions as a two-terminal voltage regulator in reverse-biased mode, maintaining stable 68 V output across a wide operating current range (10%–50% of IZM). Its low dynamic impedance (44 Ω) ensures minimal voltage variation under load transients, while its 25 °C/W junction-to-lead thermal resistance enables reliable 5 W dissipation with standard 3/8″ lead length heat sinking.

The 1N5373BE3/TR12 features a void-free UL94V-0 epoxy case, cathode band polarity marking, and moisture sensitivity level 1 per J-STD-020B-eliminating dry-pack requirements. It withstands non-recurrent 8.3 ms half-sine surge currents up to 500 A and exhibits <2.0 V voltage regulation (ΔVZ) between 10% and 50% of IZM.

Key Specifications

Pinout & Package

Package: Axial-leaded T-18 plastic case (JEDEC DO-201AD), void-free UL94V-0 epoxy body, tin-lead or RoHS-compliant matte-tin plated leads, cathode indicated by color band.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N5373BE3/TR12, the 1N5373B offers identical regulation performance but lacks RoHS compliance, while MMSZ5268B-TP trades power handling and impedance for miniaturization-making it viable only in low-current signal conditioning, not power-stage clamping.

Availability

1N5373BE3/TR12 is available at Aetrix Electronics and suitable for industrial power supplies, overvoltage protection circuits, and high-voltage reference designs requiring stable component supply, long-term lifecycle support, and traceable RoHS-compliant sourcing.

Supply support for 1N5373BE3/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, RF, and timing solutions for aerospace, defense, and industrial markets.

The 1N5373BE3/TR12 belongs to Microsemi's legacy 5 W axial Zener family, engineered for rugged voltage regulation in harsh-environment power systems where thermal stability, surge resilience, and long-term parametric consistency are critical.

FAQ

What is the Zener voltage tolerance of the 1N5373BE3/TR12?

The 1N5373BE3/TR12 has a nominal Zener voltage of 68 V with ±5% tolerance, as indicated by the "B" suffix in its part number. This means the actual V_Z falls between 64.6 V and 71.4 V at 20 mA test current and 25 °C lead temperature. The e3 suffix confirms RoHS-compliant plating but does not affect voltage tolerance.

Can the 1N5373BE3/TR12 be used without a heatsink?

The 1N5373BE3/TR12 can dissipate up to 5 W only when the lead temperature (TL) is maintained below 25 °C-typically requiring at least 3/8″ (10 mm) of lead length acting as a thermal path. Without external heatsinking or sufficient copper area, power must be derated per Figure 1 in the datasheet; on FR4 with 4 mm² pads, max steady-state power drops to 1.47 W at 25 °C ambient.

What does the "TR12" suffix indicate in 1N5373BE3/TR12?

The "TR12" suffix denotes tape-and-reel packaging per EIA-296 standard, with 12,000 units per reel. This format supports automated SMT placement despite the axial-leaded T-18 package, enabling high-volume manufacturing. The base part remains electrically and mechanically identical to bulk or ammo-pack versions of 1N5373BE3.

How does the 1N5373BE3/TR12 perform under surge conditions?

The 1N5373BE3/TR12 is rated for a non-recurrent 8.3 ms half-sine surge current of 500 A, verified per JEDEC test methods. This enables reliable clamping of lightning-induced transients or inductive kickback in industrial controls. Performance assumes proper PCB layout with low-inductance grounding and adequate trace width to handle peak current without fusing.

Is the 1N5373BE3/TR12 suitable for precision reference applications?

Yes-the 1N5373BE3/TR12 supports precision use cases due to its ±5% V_Z tolerance, low 44 Ω dynamic impedance, and 2.0 V voltage regulation (ΔV_Z) across 10–50% of I_ZM. However, for sub-1% absolute accuracy, external trimming or temperature compensation is recommended, as the device lacks built-in tempco compensation.