Microchip Technology 1N5373CE3/TR12

Overview

1N5373CE3/TR12 from Microsemi is a 5 W axial-leaded silicon Zener diode with nominal regulation voltage of 68 V, ±2% tolerance (C suffix), 20 mA test current, 44 Ω dynamic impedance at IZT, and maximum reverse current of 0.5 μA at 51.7 V. It operates from –65°C to +150°C and is used for precision voltage reference and overvoltage protection in industrial power supplies.

For engineers reviewing the 1N5373CE3/TR12 datasheet, 1N5373CE3/TR12 pinout, 1N5373CE3/TR12 application, or 1N5373CE3/TR12 equivalent, key selection criteria include Zener voltage tolerance, thermal resistance (25 °C/W junction-to-lead), surge current rating (500 A), voltage regulation (ΔVZ = 2.0 V), and RoHS-compliant matte-tin plating per MIL-STD-750.

Technical Context

This device functions as a two-terminal voltage regulator operating in reverse breakdown mode. Its Zener voltage is specified at 25°C with 20 mA test current and exhibits low dynamic impedance (44 Ω) and tight ±2% tolerance-enabled by C-suffix process control and verified per JEDEC registration.

It delivers stable regulation across wide temperature (–65°C to +150°C) and current ranges, with thermal resistance of 25 °C/W junction-to-lead at 3/8″ lead length and 85 °C/W junction-to-ambient on FR4 PCB. Surge capability is defined for non-repetitive 8.3 ms half-sine wave peaks up to 500 A.

Key Specifications

Pinout & Package

Package: Axial-leaded T-18 plastic case (Void-free transfer-molded thermosetting epoxy, UL94V-0 rated); cathode indicated by band; leads plated with RoHS-compliant annealed matte tin 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 1N5373B and MMSZ5263ET1G, the 1N5373CE3/TR12 provides superior voltage accuracy and thermal robustness for high-power linear regulation, while its axial T-18 package enables through-hole mounting with proven mechanical reliability in industrial environments.

Availability

1N5373CE3/TR12 is available at Aetrix Electronics and suitable for industrial power supplies, telecom line protection, programmable references, and sensor excitation circuits requiring stable component supply and long-term obsolescence management.

Supply support for 1N5373CE3/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 JEDEC-standardized performance, MIL-qualified screening options, and thermal resilience in axial-leaded form factor.

FAQ

What is the Zener voltage tolerance of the 1N5373CE3/TR12?

The 1N5373CE3/TR12 has a Zener voltage tolerance of ±2%, designated by the "C" suffix in the part number. This means its measured V_Z at 20 mA and 25°C falls within 66.64 V to 69.36 V. The tolerance is tighter than the ±5% of the B-suffix variant and is achieved through enhanced process control during manufacturing. This level of accuracy supports applications demanding stable reference voltages without post-assembly trimming.

How does the thermal resistance of the 1N5373CE3/TR12 affect its power handling?

The 1N5373CE3/TR12 has a junction-to-lead thermal resistance of 25 °C/W at 3/8″ lead length, meaning each watt dissipated raises the junction temperature 25°C above lead temperature. At ambient, its effective thermal resistance is 85 °C/W on FR4 with specified copper pads. To sustain full 5 W, the lead temperature must stay ≤25°C; otherwise, derating per Figure 1 applies. This makes proper lead heatsinking critical in high-power designs.

Is the 1N5373CE3/TR12 suitable for surge protection applications?

Yes, the 1N5373CE3/TR12 is rated for 500 A non-repetitive surge current (I_ZSM) under an 8.3 ms half-sine waveform, making it suitable for primary-level overvoltage clamping in telecom and industrial power systems. Its 5 W steady-state rating and low ΔV_Z (2.0 V) ensure predictable clamping behavior during transients. However, it should be coordinated with upstream fusing or current-limiting to avoid thermal runaway during sustained overloads.

What does the "e3" and "TR12" suffix indicate in 1N5373CE3/TR12?

The "e3" suffix indicates RoHS compliance with matte-tin lead plating and halogen-free epoxy encapsulation per EU Directive 2011/65/EU. The "TR12" denotes tape-and-reel packaging per EIA-296 standard, with 12,000 units per reel. This format supports automated pick-and-place assembly and ensures moisture sensitivity Level 1 handling-no dry-pack or baking required prior to soldering.

Can the 1N5373CE3/TR12 replace the 1N5373B in existing designs?

The 1N5373CE3/TR12 can replace the 1N5373B electrically and mechanically, as both share identical package (T-18), pinout, and nominal V_Z (68 V). However, the C-suffix version offers tighter ±2% tolerance versus ±5% and lower dynamic impedance (44 Ω vs. 70 Ω), improving regulation accuracy and stability. No PCB changes are needed, but system-level validation of feedback loop margin and thermal performance is recommended due to improved electrical characteristics.