Microchip Technology 1N5228A/TR

Overview

1N5228A/TR from Microsemi is a 3.9 V, ±10% tolerance, 500 mW glass axial-lead Zener diode in DO-35 (DO-204AH) package, rated for 20 mA test current and 23 Ω dynamic impedance at IZT, operating across –65°C to +175°C for voltage reference and regulation in low-power analog circuits.

For engineers reviewing the 1N5228A/TR datasheet, 1N5228A/TR pinout, 1N5228A/TR application, or 1N5228A/TR equivalent, key selection criteria include Zener voltage accuracy, thermal stability over wide temperature range, low dynamic impedance at regulation current, axial-leaded mechanical robustness, and RoHS-compliant tape-and-reel availability with "TR" suffix.

Technical Context

This discrete Zener diode operates in reverse breakdown to maintain stable DC voltage under varying load and line conditions. It features a sharp knee in the breakdown curve verified by dual-point Zener impedance measurement per MicroNote 202, ensuring unit-to-unit consistency in regulation performance.

Its hermetically sealed glass DO-35 package provides inherent radiation hardness per MicroNote 050 and ESD insensitivity (MIL-STD-750 Method 1020), with thermal resistance of 250°C/W junction-to-lead at 10 mm lead length - critical for reliability in high-temperature industrial and aerospace environments.

Key Specifications

Pinout & Package

DO-35 (DO-204AH) hermetically sealed glass axial-leaded package with cathode indicated by colored band; designed for through-hole mounting with flexible lead orientation and solderable tin-lead or RoHS-compliant matte-tin plating.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N5228A/TR, 1N4728A offers higher power headroom in a larger through-hole package, while MMBZ5228BS trades mechanical robustness and thermal performance for footprint reduction - selection depends on whether thermal management, board real estate, or field serviceability dominates the design priority.

Availability

1N5228A/TR is available at Aetrix Electronics and suitable for voltage reference, overvoltage clamping, and precision biasing applications requiring stable component supply across industrial control, aerospace subsystems, and legacy equipment maintenance programs.

Supply support for 1N5228A/TR 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, mixed-signal, and radiation-hardened components for defense, aerospace, and industrial markets.

The 1N52xx series was engineered as a JEDEC-standardized family of glass-passivated Zener diodes targeting mission-critical voltage regulation where long-term stability, wide temperature operation, and proven qualification history are mandatory.

FAQ

What is the Zener voltage tolerance of the 1N5228A/TR?

The 1N5228A/TR has a nominal Zener voltage of 3.9 V with a guaranteed tolerance of ±10%, as indicated by the "A" suffix per Microsemi's datasheet. This means the actual measured voltage at 20 mA test current falls between 3.51 V and 4.29 V at 25°C. The tolerance remains valid across the full operating temperature range of –65°C to +175°C, though voltage drift is further constrained by its –0.060 %/°C temperature coefficient.

Does the 1N5228A/TR have a defined polarity marking?

Yes, the 1N5228A/TR uses a visible cathode band on the glass body to indicate polarity. The banded end is the cathode and must be connected to the more positive potential in the circuit for proper Zener regulation. The non-banded end is the anode and connects to ground or the lower-potential node. This marking complies with JEDEC DO-35 standards and is verified in Microsemi's mechanical drawings and packaging specifications.

What is the maximum power dissipation of the 1N5228A/TR at 70°C ambient?

Per the derating curve in Microsemi's datasheet, the 1N5228A/TR maintains 500 mW dissipation up to 50°C ambient temperature. Above that, it derates linearly at 4 mW/°C. At 70°C ambient, the maximum allowable power is 420 mW (500 mW – [20°C × 4 mW/°C]). This assumes mounting on FR4 with specified copper pad geometry; junction-to-lead thermal resistance remains 250°C/W regardless of ambient, enabling accurate thermal modeling.

Is the 1N5228A/TR RoHS compliant?

Yes, the 1N5228A/TR is RoHS compliant when ordered with the "e3" suffix (e.g., 1N5228Ae3/TR). The base part number without "e3" uses traditional tin-lead plating, while the "e3" variant substitutes annealed matte-tin per MIL-STD-750 Method 2026. Both versions share identical electrical and thermal specifications, and the "TR" suffix confirms tape-and-reel packaging per EIA-296 - making RoHS compliance a selectable option without performance trade-offs.

Can the 1N5228A/TR replace older 1N5228 parts in existing designs?

Yes, the 1N5228A/TR is a direct functional and mechanical replacement for legacy 1N5228 devices, retaining identical DO-35 package dimensions, pinout, and JEDEC registration. Its ±10% tolerance, 3.9 V nominal voltage, and 23 Ω Zener impedance match the original specification. The "TR" suffix adds EIA-296 tape-and-reel packaging, supporting modern assembly while preserving compatibility with hand-soldered or wave-soldered legacy boards.