Microchip Technology 1N983B

Overview

1N983B from Microsemi is a silicon 500 mW axial-leaded Zener diode in DO-35 (DO-204AH) package, rated for 82 V nominal Zener voltage with ±5% tolerance, 1.5 mA Zener test current, 330 Ω dynamic impedance at I_ZT, and maximum 4.6 mA DC Zener current. It operates across –65°C to +175°C and serves as a precision voltage reference or overvoltage clamp in power supply feedback loops.

For engineers reviewing the 1N983B datasheet, 1N983B pinout, 1N983B application, or 1N983B equivalent, key selection criteria include its 82 V regulation point, low 0.25 mA reverse leakage at 5 V, +0.098 %/°C temperature coefficient, DO-35 mechanical compatibility, and suitability for industrial power conditioning where stable low-power voltage reference is required.

Technical Context

The 1N983B functions as a two-terminal voltage regulator operating in reverse breakdown, with Zener voltage defined at 1.5 mA test current and characterized by a sharp knee due to metallurgical bond construction. Its thermal resistance is 250 °C/W junction-to-lead (3/8″ lead length) and 310 °C/W junction-to-ambient on FR4 board.

It exhibits minimal capacitance per Figure 3, nonsensitive ESD behavior per MIL-STD-750 Method 1020, and inherent radiation hardness documented in MicroNote 050. Forward voltage is ≤1.3 V at 200 mA, confirming standard silicon P-N junction behavior.

Key Specifications

Pinout & Package

Package: DO-35 (DO-204AH), hermetically sealed axial-leaded glass body with tin-lead or RoHS-compliant matte-tin plating. Cathode indicated by band; device operated with banded end positive for Zener regulation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N983B, the 1N4742A serves lower-voltage applications with greater power headroom but incompatible pinout and voltage range, while BZX55-C82 matches voltage and package but trades regulation precision for broader vendor availability and cost.

Availability

1N983B is available at Aetrix Electronics and suitable for industrial power supplies, overvoltage protection circuits, and radiation-hardened sensor interfaces requiring stable component supply with guaranteed long-term continuity.

Supply support for 1N983B 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-voltage analog components for aerospace, defense, and industrial markets.

The 1N957B–1N992B series was designed specifically for robust, low-power voltage regulation in harsh environments-emphasizing wide temperature operation, ESD immunity, and proven radiation tolerance without external hardening.

FAQ

What is the Zener voltage tolerance for the 1N983B?

The 1N983B has a nominal Zener voltage of 82 V with a ±5% tolerance, as indicated by the "B" suffix per JEDEC registration. This means the actual measured V_Z at 1.5 mA test current falls between 77.9 V and 86.1 V at 25°C. The tolerance remains valid across the full operating temperature range of –65°C to +175°C, though voltage drift follows the +0.098 %/°C coefficient.

Can the 1N983B be used in surface-mount designs?

No, the 1N983B is packaged exclusively in the axial-leaded DO-35 (DO-204AH) glass case and is not a surface-mount device. For SMT equivalents, Microsemi offers the MLL983B in DO-213AA (MELF) package - same 82 V rating and electrical specs, but requiring reflow-compatible layout and soldering profile.

What is the maximum power dissipation of the 1N983B at room temperature?

The 1N983B is rated for 500 mW steady-state power dissipation at lead temperature (T_L) below 50°C, measured 3/8″ from the body. When mounted on an FR4 PCB with specified copper pads (4 mm²) and traces, its derated power is 480 mW at 25°C ambient. Exceeding these limits risks thermal runaway or parametric shift.

Does the 1N983B require external ESD protection?

No, the 1N983B is nonsensitive to ESD per MIL-STD-750 Method 1020 and does not require external ESD protection during handling or in-circuit operation. Its glass DO-35 construction and internal structure inherently suppress electrostatic discharge effects, making it suitable for direct integration into unshielded industrial assemblies.

How does the temperature coefficient affect regulation accuracy of the 1N983B?

The 1N983B has a +0.098 %/°C temperature coefficient, meaning its Zener voltage increases by approximately 80.4 mV per °C rise from 25°C. Over a –40°C to +85°C range, this results in a total shift of ~9.8 V - critical for precision references. Designers must either compensate thermally or limit operating ΔT to maintain ±1% regulation accuracy.