Microchip Technology 1N5231A

Overview

1N5231A from Microsemi is a 5.1 V, ±10% tolerance, 500 mW glass axial-lead Zener diode in DO-35 (DO-204AH) package, rated for 20 mA test current and 17 Ω dynamic impedance at IZT, used for precision voltage regulation and reference in low-power analog circuits.

For engineers reviewing the 1N5231A datasheet, 1N5231A pinout, 1N5231A application, or 1N5231A equivalent, this part serves as a stable, temperature-compensated voltage reference in power supply feedback loops, overvoltage protection clamps, and analog signal conditioning where tight thermal drift and low leakage (<50 µA @ 3.8 V) are critical.

Technical Context

The 1N5231A operates as a reverse-biased silicon Zener diode with a sharp breakdown knee at 5.1 V, exhibiting a positive temperature coefficient of +0.030 %/°C - enabling predictable drift compensation in multi-diode references. Its DO-35 glass package ensures hermetic sealing and radiation hardness per MicroNote 050.

It delivers stable regulation across –65°C to +175°C, with thermal resistance of 250 °C/W junction-to-lead (3/8″ lead length) and 310 °C/W junction-to-ambient on FR4. Forward voltage is ≤1.5 V at 200 mA, confirming robust conduction capability during transient forward bias.

Key Specifications

Pinout & Package

DO-35 (DO-204AH) hermetically sealed glass axial-leaded package; cathode indicated by color band - device must be reverse-biased (banded end positive) for Zener operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N5231A, 1N4733A offers higher power and relaxed thermal constraints but requires PCB redesign; BZX55C5V1 provides better initial accuracy but less predictable temperature tracking - making 1N5231A optimal for thermally stable, space-constrained 500 mW reference designs.

Availability

1N5231A is available at Aetrix Electronics and suitable for power supply feedback reference, overvoltage clamp protection, and analog signal level shifting requiring stable component supply across aerospace, industrial control, and test equipment programs.

Supply support for 1N5231A 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, RF, and radiation-hardened components for defense, aerospace, and industrial markets.

The 1N52xx series was designed specifically for precision voltage reference and regulation in harsh-environment systems where long-term stability, wide temperature operation, and hermetic reliability are mandatory.

FAQ

What is the Zener voltage tolerance of the 1N5231A?

The 1N5231A has a nominal Zener voltage of 5.1 V with a guaranteed tolerance of ±10%, as indicated by the "A" suffix per JEDEC specification. This means the actual breakdown voltage falls between 4.59 V and 5.61 V when measured at 20 mA and 25°C. The tolerance is verified during production screening and applies across the full operating temperature range.

Does the 1N5231A require heatsinking in standard PCB mounting?

No, the 1N5231A does not require external heatsinking when operated within its 500 mW rating and mounted with ≥3/8″ (10 mm) lead length from the glass body. Its junction-to-lead thermal resistance is 250 °C/W, allowing safe operation up to 25°C ambient at full power. On FR4 with 4 mm² copper pads, derating begins above 25°C ambient per Figure 1.

Can the 1N5231A be used in place of a 1N4733A?

The 1N5231A is not a direct replacement for the 1N4733A due to differences in power rating (500 mW vs. 1 W), package (DO-35 vs. DO-41), and tolerance (±10% vs. ±5%). While both regulate at 5.1 V, substituting 1N5231A into a 1N4733A design risks thermal overload and reduced accuracy unless current and layout are re-verified.

What is the maximum reverse leakage current for the 1N5231A?

The 1N5231A specifies a maximum reverse leakage current (IR) of 50 µA when measured at VR = 3.8 V - approximately 75% of its nominal Zener voltage. This low leakage supports high-impedance bias networks and minimizes error in precision reference applications where input current must remain below 100 nA.

Is the 1N5231A RoHS compliant?

Yes - the RoHS-compliant version of the 1N5231A is designated as 1N5231Ae3, with annealed matte-tin plating per MIL-STD-750 Method 2026. Standard 1N5231A uses tin-lead finish; the "e3" suffix confirms lead-free compliance without altering electrical or thermal specifications.