Microchip Technology 1N5226B

Overview

1N5226B from Microsemi is a 3.3 V, ±5% tolerance, 500 mW glass axial-lead Zener diode in DO-35 (DO-204AH) package, rated for 20 mA test current and 28 Ω dynamic impedance at IZT, used for precision voltage regulation in low-power analog reference and bias circuits.

For engineers reviewing the 1N5226B datasheet, 1N5226B pinout, 1N5226B application, or 1N5226B equivalent, this part serves as a stable, temperature-compensated shunt regulator in power supply feedback paths, sensor excitation networks, and overvoltage clamp stages where compact axial-leaded packaging and JEDEC-standard compliance are required.

Technical Context

The 1N5226B operates as a reverse-biased silicon Zener diode with sharp breakdown knee and minimal capacitance (typ. <2 pF), enabling stable regulation across -65°C to +175°C ambient range. Its thermal resistance is 250°C/W junction-to-lead at 10 mm lead length.

It delivers 3.3 V nominal regulation at 20 mA test current with 28 Ω Zener impedance (ZZT) and -0.070 %/°C temperature coefficient - optimized for low-drift reference generation in space-constrained industrial and aerospace designs.

Key Specifications

Pinout & Package

DO-35 (DO-204AH) hermetically sealed glass axial-leaded package with cathode indicated by band; banded end must be held positive relative to anode for Zener operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N5226B, the 1N4728A offers higher power headroom but requires layout revision due to DO-41 size and exhibits less favorable temperature drift; the BZX55C3V3 matches form/fit/function for DO-35 boards but lacks military screening options and JEDEC registration.

Availability

1N5226B is available at Aetrix Electronics and suitable for precision voltage reference, sensor excitation, and overvoltage clamp applications requiring stable component supply across extended temperature and radiation environments.

Supply support for 1N5226B 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, radiation-hardened, and aerospace-grade components.

The 1N52xxB series was designed for mission-critical analog reference and regulation in defense, space, and industrial control systems where long-term parametric stability and JEDEC-standard compliance are mandatory.

FAQ

What is the maximum operating temperature for the 1N5226B?

The 1N5226B has a specified operating and storage temperature range of -65°C to +175°C. This wide range supports deployment in extreme environments such as downhole oil/gas instrumentation and avionics power conditioning modules where thermal cycling reliability is critical. The 1N5226B maintains regulation integrity throughout this range without parameter shift beyond datasheet limits.

Does the 1N5226B require external heat sinking?

No, the 1N5226B does not require external heat sinking under standard operating conditions. With a 500 mW power rating and 250°C/W junction-to-lead thermal resistance at 10 mm lead length, it dissipates heat effectively through its axial leads when mounted per JEDEC guidelines. Heat sinking becomes necessary only if ambient temperature exceeds 50°C or power dissipation approaches 400 mW continuously.

How does the 1N5226B differ from the 1N5226A?

The 1N5226B has ±5% Zener voltage tolerance, while the 1N5226A has ±10%. Both share identical package (DO-35), power rating (500 mW), and test current (20 mA), but the 1N5226B provides tighter regulation for applications demanding higher reference accuracy - such as precision ADC references or closed-loop power supply feedback where output tolerance budgets are sub-1%.

Is the 1N5226B suitable for use in RoHS-compliant designs?

Yes, the 1N5226B is available in RoHS-compliant form with the "e3" suffix (e.g., 1N5226Be3), featuring annealed matte-tin plating compliant with MIL-STD-750 Method 2026. Standard 1N5226B uses tin-lead finish; the e3 variant replaces lead with compliant materials while maintaining identical electrical performance and mechanical dimensions.

Can the 1N5226B be used as a substitute for the 1N4728A?

The 1N5226B and 1N4728A both regulate at 3.3 V with ±5% tolerance, but they are not direct substitutes due to differing packages (DO-35 vs. DO-41), power ratings (500 mW vs. 1 W), and temperature coefficients (-0.070 %/°C vs. +0.075 %/°C). PCB layout changes are required, and thermal design must be re-evaluated; use only after verifying current, thermal, and drift requirements match the 1N5226B's specifications.