Microchip Technology 1N5271A

Overview

1N5271A from Microsemi is a 100 V, ±10% tolerance, 500 mW glass axial-lead Zener diode in DO-35 (DO-204AH) package, rated for 1.3 mA test current and 2600 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 low-power analog circuits, power supply feedback loops, and industrial sensor conditioning.

For engineers reviewing the 1N5271A datasheet, 1N5271A pinout, 1N5271A application, or 1N5271A equivalent, key selection criteria include its 100 V nominal Zener voltage, ±10% tolerance (A suffix), 500 mW power rating at 25°C, DO-35 mechanical form factor, and temperature coefficient of +0.110 %/°C - all critical for stable regulation under thermal stress and layout-constrained designs.

Technical Context

The 1N5271A operates in reverse-biased Zener breakdown mode with a sharp knee at 100 V, verified by dual-point Zener impedance measurement per MicroNote 202. Its 2600 Ω ZZT at IZK = 0.25 mA and 72 V maximum Zener voltage at IZT = 1.3 mA confirm stable regulation onset across production lots.

Designed for high-temperature reliability, it features 250 °C/W junction-to-lead thermal resistance at 10 mm lead length and maintains regulation integrity up to +175°C storage temperature. The device uses hermetically sealed glass construction with tin-lead plating, ensuring ESD insensitivity per MIL-STD-750 Method 1020 and inherent radiation hardness per MicroNote 050.

Key Specifications

Pinout & Package

DO-35 (DO-204AH) glass axial-leaded package: hermetically sealed cylindrical glass body with tinned copper alloy leads; cathode identified by single black band; polarity must be observed - banded end connected to higher potential during Zener operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N4764A and MMBZ5271B, the 1N5271A offers the unique combination of JEDEC-standard DO-35 axial packaging, 500 mW rating, and ±10% tolerance - making it optimal for legacy-compatible, medium-power, high-temperature through-hole designs where lead-forming flexibility and thermal resilience are prioritized over ultra-tight tolerance or surface-mount integration.

Availability

1N5271A is available at Aetrix Electronics and suitable for industrial power supply feedback, overvoltage protection clamp, and high-temperature reference source applications requiring stable component supply across extended lifecycle programs.

Supply support for 1N5271A 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 components for aerospace, defense, and industrial markets.

The 1N52xx series was designed specifically for ruggedized voltage regulation in mission-critical systems where long-term parametric stability, wide temperature operation, and hermetic reliability outweigh cost-sensitive consumer-grade alternatives.

FAQ

What is the nominal Zener voltage and tolerance of the 1N5271A?

The 1N5271A has a nominal Zener voltage of 100 V with a guaranteed tolerance of ±10%, as indicated by the "A" suffix per Microsemi's datasheet. This tolerance is verified at IZT = 1.3 mA and 25°C ambient, and the device maintains regulation integrity across its full –65°C to +175°C operating range. The 1N5271A is not rated for ±5% or tighter tolerances - those require "B", "C", or "D" suffix variants.

What package type and mounting configuration does the 1N5271A use?

The 1N5271A uses the DO-35 (DO-204AH) glass axial-leaded package with hermetically sealed construction and tin-lead solderable plating. It mounts via through-hole insertion with flexible lead forming; the cathode is marked by a single black band and must be oriented toward the higher-potential node during Zener operation. Lead length affects thermal resistance - 10 mm from body yields 250 °C/W junction-to-lead.

What is the maximum power dissipation and thermal derating behavior of the 1N5271A?

The 1N5271A is rated for 500 mW power dissipation at 25°C ambient, with linear derating above that temperature per Figure 1 in the datasheet. At 50°C lead temperature (TL), steady-state power drops to 0.5 W; on FR4 PCB with specified copper pads, derating begins at 25°C ambient. Thermal resistance is 250 °C/W junction-to-lead at 10 mm lead length, enabling reliable operation up to +175°C case temperature.

How does the temperature coefficient affect the 1N5271A's regulation voltage in real-world operation?

The 1N5271A has a positive temperature coefficient of +0.110 %/°C, meaning its Zener voltage increases by approximately 110 mV per degree Celsius rise above 25°C. For example, at 125°C ambient, the 100 V nominal voltage shifts to ~111 V. This predictable drift supports compensation in high-temp designs but requires margining in precision references where absolute stability is critical.

Is the 1N5271A suitable for ESD-sensitive applications or harsh environmental conditions?

Yes - the 1N5271A is explicitly characterized as nonsensitive to ESD per MIL-STD-750 Method 1020 and exhibits inherent radiation hardness per MicroNote 050. Its hermetic glass seal prevents moisture-induced degradation, and it operates reliably from –65°C to +175°C. These attributes make the 1N5271A appropriate for aerospace, oilfield, and industrial control environments where environmental robustness is mandatory.