Microchip Technology 1N5280B/TR

Overview

1N5280B/TR from Microsemi is a 190 V, ±5% tolerance, 500 mW glass axial-lead Zener diode in DO-35 (DO-204AH) package, rated for 0.66 mA test current and 2400 Ω dynamic impedance at 0.25 mA, operating from –65°C to +175°C. It serves as a precision voltage reference or overvoltage clamp in industrial power supplies and high-temperature sensor conditioning circuits.

For engineers reviewing the 1N5280B/TR datasheet, 1N5280B/TR pinout, 1N5280B/TR application, or 1N5280B/TR equivalent, key selection criteria include its 190 V nominal Zener voltage, ±5% tolerance (B suffix), 500 mW power rating at 25°C, DO-35 hermetic glass package, and temperature coefficient of +0.110 %/°C - all critical for stable regulation under thermal stress.

Technical Context

This Zener diode operates in reverse breakdown mode with cathode band marking polarity, requiring the banded end to be held positive relative to the anode for regulation. Its 2400 Ω Zener impedance at IZK = 0.25 mA and 108 V maximum Zener voltage at IZT confirm sharp knee behavior per JEDEC registration.

The device exhibits minimal capacitance across its voltage range (per Figure 2), supports soldering at 260°C for 10 s, and maintains regulation over –65°C to +175°C with thermal resistance of 250°C/W junction-to-lead at 3/8″ lead length.

Key Specifications

Pinout & Package

DO-35 (DO-204AH) hermetically sealed glass axial-leaded package with tin-lead or RoHS-compliant matte-tin plating; cathode identified by color band.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N5280C/TR and MMBZ5280B-TP, the 1N5280B/TR delivers optimal trade-off of hermetic reliability, high-temperature capability, and JEDEC-standardized ±5% tolerance - making it preferred for industrial and aerospace applications where long-term stability outweighs ultra-tight tolerance or miniaturization.

Availability

1N5280B/TR is available at Aetrix Electronics and suitable for high-voltage reference design, overvoltage clamping, and high-temperature sensor signal conditioning requiring stable component supply across extended lifecycle programs.

Supply support for 1N5280B/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 and mixed-signal components for aerospace, defense, and industrial markets.

The 1N52xxB series belongs to Microsemi's legacy DO-35 Zener diode product line, engineered for precision voltage regulation in harsh-environment applications demanding hermetic sealing, wide temperature range, and radiation tolerance.

FAQ

What is the nominal Zener voltage and tolerance of the 1N5280B/TR?

The 1N5280B/TR has a nominal Zener voltage of 190 V with a guaranteed tolerance of ±5%, indicated by the "B" suffix per JEDEC standards. This tolerance applies across the full operating temperature range of –65°C to +175°C and is verified at 0.66 mA test current (IZT). The 1N5280B/TR is not rated for tighter tolerances such as ±2% or ±1% - those require C or D suffix variants.

What package type and mounting configuration does the 1N5280B/TR use?

The 1N5280B/TR uses the DO-35 (DO-204AH) hermetically sealed glass axial-leaded package with tin-lead or RoHS-compliant matte-tin plating. It features flexible axial-lead mounting and requires 3/8″ (10 mm) minimum lead length from the body for thermal resistance specification. The cathode is marked by a visible band, and the device must be operated with the banded end positive relative to the anode.

What is the maximum power dissipation and thermal derating behavior of the 1N5280B/TR?

The 1N5280B/TR is rated for 500 mW power dissipation at 25°C ambient or lead temperature. Derating begins linearly beyond 25°C, reaching zero power at approximately 150°C per the published derating curve (Figure 1). Junction-to-lead thermal resistance is 250°C/W at 3/8″ lead length; junction-to-ambient is 310°C/W on FR4 board with specified copper layout. Exceeding these limits risks parametric shift or failure.

Is the 1N5280B/TR suitable for high-reliability or military applications?

Yes - the 1N5280B/TR is JEDEC-registered and supports optional MIL-PRF-19500 screening (JAN, JANTX, JANTXV, JANS) when ordered with appropriate prefixes and the "-1" suffix. Its hermetic DO-35 construction, radiation hardness per MicroNote 050, ESD insensitivity (MIL-STD-750 Method 1020), and –65°C to +175°C operating range make it suitable for aerospace, defense, and downhole industrial systems.

How does the temperature coefficient affect the 1N5280B/TR's regulation accuracy?

The 1N5280B/TR has a temperature coefficient (αVZ) of +0.110 %/°C, meaning its Zener voltage increases by approximately 0.209 V per 10°C rise above 25°C. Over a 100°C span (e.g., 25°C to 125°C), this contributes ~10.5 V drift. System-level accuracy must account for this alongside initial ±5% tolerance and thermal resistance effects - the 1N5280B/TR is optimized for stability within defined thermal boundaries, not ultra-low-drift operation.