Microchip Technology 1N5258B

Overview

1N5258B from Microsemi is a 36 V, ±5% tolerance, 500 mW glass axial-lead Zener diode in DO-35 (DO-204AH) package, rated for 3.4 mA test current, 70 Ω dynamic impedance at IZK, and operating from –65°C to +175°C. It provides stable voltage regulation in low-power reference and protection circuits such as power supply feedback paths and overvoltage clamp stages.

For engineers reviewing the 1N5258B datasheet, 1N5258B pinout, 1N5258B application, or 1N5258B equivalent, key selection criteria include its 36 V nominal Zener voltage, 500 mW power rating at 25°C, DO-35 mechanical form factor, ±5% tolerance (B suffix), and temperature coefficient of +0.093 %/°C - all critical for precision biasing and thermal-stable clamping designs.

Technical Context

This discrete Zener diode operates in reverse breakdown mode with cathode band indicating polarity. Its regulation performance is specified at 3.4 mA test current (IZT), with dynamic impedance measured at 0.25 mA (IZK) yielding 70 Ω - ensuring predictable knee behavior under light-load conditions.

The device exhibits a positive temperature coefficient (+0.093 %/°C), confirming increasing VZ with rising junction temperature - a key consideration when designing across wide ambient ranges. Thermal resistance is 250 °C/W junction-to-lead (3/8″ lead length) and 310 °C/W junction-to-ambient on FR4 board, defining safe derating boundaries.

Key Specifications

Pinout & Package

DO-35 (DO-204AH) hermetically sealed glass axial-leaded package with cathode indicated by a single dark 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 regulation applications.

Compared with 1N4749A and BZX55-C36, the 1N5258B offers optimal balance of DO-35 compatibility, low 70 Ω Zz at 0.25 mA, and proven radiation hardness - making it preferred for space-constrained, high-reliability, or radiation-exposed designs where 500 mW suffices.

Availability

1N5258B is available at Aetrix Electronics and suitable for voltage reference, overvoltage protection, and low-power power supply feedback applications requiring stable component supply, long-term obsolescence management, and traceable sourcing.

Supply support for 1N5258B 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 military, industrial, and space applications demanding extended temperature operation, hermetic packaging, and JEDEC-standardized Zener performance with guaranteed parametric limits.

FAQ

What is the nominal Zener voltage and tolerance of the 1N5258B?

The 1N5258B has a nominal Zener voltage of 36 V with a tolerance of ±5%, as indicated by the "B" suffix per Microsemi's documentation. This tolerance is guaranteed across the full operating temperature range of –65°C to +175°C, and the voltage is specified at a test current of 3.4 mA (IZT). The 1N5258B meets JEDEC registration requirements for the 1N52xx family, ensuring consistent performance versus legacy designs.

What package type and marking does the 1N5258B use?

The 1N5258B uses the DO-35 (DO-204AH) hermetically sealed glass axial-leaded package with cathode identified by a single dark band. The device is marked with its full part number "1N5258B" on the body. Lead finish is either tin-lead or RoHS-compliant matte-tin plating, qualified per MIL-STD-750 Method 2026 for solderability, and supports 260°C for 10 seconds during reflow.

What is the Zener impedance and test condition for the 1N5258B?

The 1N5258B has a maximum Zener impedance (ZZK) of 70 Ω, measured at IZK = 0.25 mA. This value reflects dynamic impedance near the knee of the breakdown curve and ensures stable regulation under light-load or standby conditions. The 1N5258B also specifies ZZT = 700 Ω at IZT = 3.4 mA, confirming predictable voltage deviation under nominal operating current.

Does the 1N5258B have radiation hardness and ESD immunity?

Yes, the 1N5258B is inherently radiation hard per MicroNote 050 and nonsensitive to ESD per MIL-STD-750 Method 1020. These characteristics are intrinsic to its DO-35 glass construction and processing, requiring no additional qualification testing. The 1N5258B is widely deployed in aerospace, defense, and nuclear instrumentation systems where total ionizing dose (TID) resilience and handling robustness are mandatory.

How does the temperature coefficient of the 1N5258B affect its regulation stability?

The 1N5258B has a temperature coefficient (αVZ) of +0.093 %/°C, meaning its Zener voltage increases by approximately 33.5 mV per °C rise in junction temperature. This positive TC is typical for Zeners above ~6 V and must be accounted for in precision references; however, it enables predictable compensation when paired with negative-TC elements like silicon junctions in bias networks.