Microchip Technology 1N5227B

Overview

1N5227B from Microsemi is a 500 mW, 3.6 V ±5% glass axial-lead Zener diode in DO-35 (DO-204AH) package, rated for -65°C to +175°C operation, with 24 Ω zener impedance at 20 mA test current and 15 μA max reverse leakage at 2.88 V. It serves as a precision voltage reference in low-power analog circuits, power supply feedback paths, and overvoltage protection clamps.

For engineers reviewing the 1N5227B datasheet, 1N5227B pinout, 1N5227B application, or 1N5227B equivalent, key selection factors include its 3.6 V nominal regulation voltage, ±5% tolerance (B suffix), 24 Ω dynamic impedance, temperature coefficient of -0.065 %/°C, and suitability for high-reliability, wide-temperature industrial and aerospace designs requiring stable low-voltage reference.

Technical Context

The 1N5227B operates as a two-terminal voltage reference device, conducting in reverse breakdown to maintain a stable 3.6 V across its terminals within specified current and temperature limits. Its DO-35 glass package provides hermetic sealing and inherent radiation hardness per MicroNote 050.

It exhibits a negative temperature coefficient (-0.065 %/°C), indicating decreasing Zener voltage with rising temperature - a critical design factor when used in temperature-sensitive biasing or compensation networks. Reverse leakage is limited to 15 μA at 2.88 V, supporting low-quiescent-current applications.

Key Specifications

Pinout & Package

DO-35 (DO-204AH) hermetically sealed glass axial-leaded package with cathode indicated by a single black band; leads are tin-lead or RoHS-compliant matte-tin plated, solderable per MIL-STD-750 Method 2026.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N5227B, the 1N4728A offers lower voltage and better impedance but requires mechanical redesign, while the BZX55-C3V6 matches voltage and package but omits radiation hardness and military screening - making 1N5227B the sole choice for high-reliability aerospace or defense applications demanding both 3.6 V regulation and inherent radiation tolerance.

Availability

1N5227B is available at Aetrix Electronics and suitable for industrial control systems, aerospace avionics, and downhole oilfield instrumentation requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for 1N5227B 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 high-temperature analog and mixed-signal components.

The 1N5227B belongs to Microsemi's legacy 1N52xxB Zener series designed for precision voltage regulation in mission-critical systems where extended temperature operation, ESD immunity, and radiation tolerance are mandatory.

FAQ

What is the nominal Zener voltage and tolerance of the 1N5227B?

The 1N5227B has a nominal Zener voltage of 3.6 V with a tolerance of ±5%, as indicated by the "B" suffix per JEDEC specification. This means its actual breakdown voltage falls between 3.42 V and 3.78 V at 20 mA test current and 25°C ambient temperature. The 1N5227B achieves this tight tolerance through factory binning and is guaranteed across its full operating temperature range.

What is the maximum power dissipation rating for the 1N5227B and how does it derate with temperature?

The 1N5227B is rated for 500 mW power dissipation at 25°C case temperature (TL), with linear derating to zero at 175°C. Derating follows a slope of 4.0 mW/°C above 25°C when lead length is maintained at 3/8 inch (10 mm) from the glass body. When mounted on FR4 with specified copper pads, steady-state power drops to 480 mW at 25°C ambient due to higher thermal resistance.

Does the 1N5227B have radiation hardness certification, and what standard applies?

Yes, the 1N5227B is inherently radiation hard per MicroNote 050, a proprietary Microsemi characterization confirming performance stability under total ionizing dose (TID) exposure. While not certified to MIL-STD-883 Class B or ESA ESCC specifications out-of-the-box, its glass-encapsulated DO-35 construction and process design provide demonstrated resilience in low-earth orbit and nuclear environments without additional qualification testing.

What is the Zener impedance of the 1N5227B and why does it matter in circuit design?

The 1N5227B has a maximum Zener impedance (ZZT) of 24 Ω measured at 20 mA test current. This value reflects the dynamic resistance in the breakdown region and directly impacts regulation accuracy under varying load currents. A lower ZZT improves line and load regulation - for example, a 10 mA load change causes only ~240 mV output shift, critical in precision analog references and feedback loops where stability is paramount.

Can the 1N5227B be used in surface-mount designs, and what is the closest SMT equivalent?

No, the 1N5227B is axial-leaded DO-35 and not surface-mount compatible. The closest functional SMT equivalent is the MLL5227B in DO-213AA (MELF) package, which shares identical electrical specs including 3.6 V ±5%, 24 Ω Z_ZT, and -0.065 %/°C tempco. MLL5227B requires reflow profile validation but enables automated assembly and improved thermal cycling reliability in compact PCB layouts.