Microchip Technology 1N5231B/TR

Overview

1N5231B/TR from Microsemi is a 5.1 V, ±5% 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 in low-power analog reference and overvoltage protection circuits.

For engineers reviewing the 1N5231B/TR datasheet, 1N5231B/TR pinout, 1N5231B/TR application, or 1N5231B/TR equivalent, this page delivers verified electrical specs, thermal derating behavior, Zener voltage temperature coefficient (+0.030 %/°C), RoHS-compliant packaging with "e3" option, and tape-and-reel availability via "TR" suffix.

Technical Context

This discrete Zener diode operates in reverse breakdown to maintain stable output voltage across varying load currents (0.25–20 mA) and temperatures (−65°C to +175°C). Its 17 Ω Zener impedance at 20 mA ensures low regulation error under dynamic load conditions.

The device uses a hermetically sealed glass DO-35 package with tin-lead or annealed matte-tin plating, cathode indicated by band, and exhibits minimal capacitance (<2.0 pF typical per Figure 2) - critical for high-frequency noise suppression and clean reference generation.

Key Specifications

Pinout & Package

DO-35 (DO-204AH) glass axial-leaded package: hermetically sealed, 0.2 g weight, cathode identified by single black band; leads are tinned and 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 1N4733A and BZX55C5V1, the 1N5231B/TR offers optimal balance of DO-35 footprint compatibility, 17 Ω regulation stiffness at 20 mA, and dual-availability in leaded and RoHS versions - making it ideal for legacy design refreshes requiring drop-in replacement with verified thermal and electrical behavior.

Availability

1N5231B/TR is available at Aetrix Electronics and suitable for voltage reference generators, overvoltage clamp circuits, and low-power bias supplies requiring stable component supply across automotive infotainment, industrial PLC I/O modules, and medical sensor interfaces.

Supply support for 1N5231B/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, mixed-signal, and radiation-hardened components for aerospace, defense, and industrial markets.

The 1N52xxB series was designed specifically for precision voltage regulation in mission-critical systems where long-term stability, wide temperature operation, and JEDEC-standard compatibility are mandatory.

FAQ

What is the Zener voltage tolerance for 1N5231B/TR?

The "B" suffix in 1N5231B/TR specifies a ±5% tolerance on the nominal 5.1 V Zener voltage, meaning the actual measured VZ at 20 mA and 25°C falls between 4.845 V and 5.355 V. This tolerance is guaranteed per JEDEC specification and applies across the full operating temperature range of −65°C to +175°C for the 1N5231B/TR.

Does 1N5231B/TR support RoHS compliance?

Yes - the 1N5231B/TR can be ordered with the "e3" suffix (e.g., 1N5231B-e3/TR) to indicate RoHS-compliant matte-tin plating. The base 1N5231B/TR uses traditional tin-lead plating per MIL-STD-750 Method 2026, but the e3 variant meets EU Directive 2011/65/EU without altering electrical or thermal specifications of the 1N5231B/TR.

What is the maximum power dissipation of 1N5231B/TR at 75°C ambient?

Per Figure 1 derating curve, the 1N5231B/TR's power dissipation linearly decreases from 500 mW at 25°C to zero at 175°C. At 75°C ambient, the allowable power is 500 mW × (1 − (75 − 25)/150) = 333 mW. This assumes mounting on FR4 with 4 mm² copper pads; actual value depends on thermal path per the 310°C/W junction-to-ambient spec for the 1N5231B/TR.

How does the temperature coefficient affect 1N5231B/TR in a 50°C temperature rise?

With a specified αVZ of +0.030 %/°C, a 50°C rise from 25°C causes a +1.5% shift in nominal 5.1 V - i.e., +76.5 mV. So the 1N5231B/TR's regulated voltage increases to approximately 5.176 V at 75°C, assuming constant current. This predictable drift enables compensation in precision references using the 1N5231B/TR.

Can 1N5231B/TR replace 1N5231A in existing designs?

Yes - both share identical DO-35 package, 5.1 V nominal voltage, and same pinout, but 1N5231B/TR has tighter ±5% tolerance versus ±10% for the "A" suffix. No layout change is needed; however, the improved tolerance may reduce calibration overhead in systems using the 1N5231B/TR as a reference, and leakage current differs slightly (50 μA vs. 100 μA at VR).