Microchip Technology 1N5248B/TR

Overview

1N5248B/TR from Microsemi is a 500 mW, 18 V ±5% glass axial-lead Zener diode in DO-35 (DO-204AH) package, rated for -65°C to +175°C operation, with 7.0 Ω zener impedance at 7.0 mA test current and 0.1 μA max reverse leakage at 14.4 V. It serves as a precision voltage reference in low-power analog circuits, power supply feedback loops, and overvoltage protection clamps.

For engineers reviewing the 1N5248B/TR datasheet, 1N5248B/TR pinout, 1N5248B/TR application, or 1N5248B/TR equivalent, key selection criteria include its 18 V nominal zener voltage, ±5% tolerance (B suffix), 500 mW power rating at 25°C, DO-35 mechanical form factor, and temperature coefficient of +0.085 %/°C - all critical for stable regulation in industrial and aerospace environments.

Technical Context

This discrete Zener diode operates in reverse breakdown mode with a sharp knee at 7.0 mA test current (IZT), delivering stable regulation across a wide current range (0.25 mA to 7.0 mA). Its glass DO-35 package provides hermetic sealing and inherent radiation hardness per MicroNote 050.

Thermal resistance is 250 °C/W junction-to-lead (3/8″ lead length) and 310 °C/W junction-to-ambient on FR4 board; forward voltage is ≤1.5 V at 200 mA. It exhibits minimal capacitance (<2 pF typical) and is ESD-nonsensitive per MIL-STD-750 Method 1020.

Key Specifications

Pinout & Package

DO-35 (DO-204AH) hermetically sealed glass axial-leaded package with cathode indicated by color band; diode must be biased with 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 1N5248B/TR, 1N4746A offers higher power headroom at the cost of larger size and poorer thermal efficiency, while MMBZ5248B enables miniaturization and SMT production but sacrifices 30% power rating and 25°C upper temperature margin.

Availability

1N5248B/TR is available at Aetrix Electronics and suitable for industrial power supply feedback, aerospace voltage reference, and overvoltage clamp protection requiring stable component supply, full traceability, and extended temperature support.

Supply support for 1N5248B/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 was designed specifically for ruggedized voltage regulation in mission-critical systems where extended temperature operation, radiation tolerance, and JEDEC-standard interchangeability are mandatory.

FAQ

What is the nominal Zener voltage and tolerance of the 1N5248B/TR?

The 1N5248B/TR has a nominal Zener voltage of 18 V with a ±5% tolerance, as indicated by the "B" suffix per JEDEC specification. This means its actual breakdown voltage falls between 17.1 V and 18.9 V at 25°C and 7.0 mA test current. The tolerance is guaranteed across the full operating temperature range of -65°C to +175°C, making it suitable for high-reliability applications where voltage stability is critical.

What package type and mounting configuration does the 1N5248B/TR use?

The 1N5248B/TR uses a DO-35 (DO-204AH) hermetically sealed glass axial-leaded package. It features flexible through-hole mounting with cathode identified by a visible color band on the banded end. For proper Zener operation, the banded (cathode) end must be biased positively relative to the anode. Lead length is specified at ≥3/8″ (10 mm) from the body for thermal rating compliance.

How does the temperature coefficient affect the 1N5248B/TR's regulation accuracy?

The 1N5248B/TR has a positive temperature coefficient of +0.085 %/°C, meaning its Zener voltage increases by approximately 15.3 mV per 1°C rise above 25°C. This behavior is well-characterized and repeatable, enabling predictable compensation in precision reference designs. At 125°C, the voltage shift is ~8.5 V, so system-level calibration must account for this drift if sub-1% absolute accuracy is required across temperature.

Is the 1N5248B/TR RoHS compliant, and how is compliance indicated?

Yes, RoHS-compliant versions of the 1N5248B/TR are available with the "e3" suffix (e.g., 1N5248B-e3/TR), indicating annealed matte-tin plating per MIL-STD-750 Method 2026. The base 1N5248B/TR part uses traditional tin-lead plating unless otherwise specified. Both variants share identical electrical and thermal specifications; only the finish differs to meet environmental directives.

What is the maximum reverse leakage current for the 1N5248B/TR, and at what voltage is it specified?

The 1N5248B/TR has a maximum reverse leakage current (IR) of 0.1 μA, measured at a reverse voltage (VR) of 14.4 V - which is 80% of its nominal 18 V Zener voltage. This ultra-low leakage ensures minimal quiescent current draw in battery-powered or high-impedance reference circuits, preserving signal integrity and extending operational life in low-power systems.