Microchip Technology 1N976B

Overview

1N976B from Microsemi is a silicon 500 mW axial-leaded Zener diode in DO-35 (DO-204AH) package, rated for 43 V nominal Zener voltage at 3.0 mA test current, with ±5% tolerance, 1500 Ω dynamic impedance at I_ZT, and +0.095 %/°C temperature coefficient. It regulates voltage in low-power reference and protection circuits across industrial temperature range.

For engineers reviewing the 1N976B datasheet, 1N976B pinout, 1N976B application, or 1N976B equivalent, key selection criteria include its 43 V regulation point, 8.8 mA maximum DC Zener current, 44 mA surge capability, -65°C to +175°C operating range, and glass-body DO-35 mechanical robustness for high-reliability analog signal conditioning.

Technical Context

The 1N976B operates as a reverse-biased voltage reference device, maintaining stable 43 V output across a wide current range (0.25–8.8 mA) with minimal thermal drift due to its +0.095 %/°C coefficient. Its 1500 Ω Zener impedance at 3.0 mA ensures predictable regulation knee behavior under varying load conditions.

Designed for through-hole mounting, it features hermetically sealed glass construction, tin-lead or RoHS-compliant matte-tin plating, cathode band polarity marking, and JEDEC-registered compliance. It exhibits <5 μA reverse leakage at 32.7 V and withstands 260 °C soldering for 10 s.

Key Specifications

Pinout & Package

Package: DO-35 (DO-204AH), hermetically sealed axial-leaded glass body, 0.2 g weight, cathode indicated by colored band. Terminals are tin-lead or RoHS-compliant matte-tin plated, solderable per MIL-STD-750 Method 2026.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N976B, 1N4749A offers higher power margin but requires board rework for DO-41; BZX55-C43 matches DO-35 form factor and power but lacks radiation hardening and MIL-STD-750 ESD validation, making 1N976B preferable for aerospace and high-reliability industrial use.

Availability

1N976B is available at Aetrix Electronics and suitable for industrial power supply reference, automotive sensor biasing, aerospace signal conditioning, and test equipment calibration requiring stable component supply across extended temperature and radiation environments.

Supply support for 1N976B 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 defense, aerospace, and industrial markets.

The 1N957B–1N992B series was designed specifically for ruggedized voltage regulation in mission-critical systems where long-term stability, ESD immunity, and extreme temperature operation are mandatory.

FAQ

What is the nominal Zener voltage and tolerance of the 1N976B?

The 1N976B has a nominal Zener voltage of 43 V with a ±5% tolerance, as defined by the "B" suffix per JEDEC registration. This tolerance is verified at 25°C with 3.0 mA test current and applies across the full operating temperature range of -65°C to +175°C. The 1N976B maintains this specification without requiring external trimming or calibration.

What package type and mounting configuration does the 1N976B use?

The 1N976B uses the DO-35 (DO-204AH) axial-leaded glass package with hermetically sealed construction. It is designed for through-hole mounting, with cathode identified by a visible band on the glass body. The 1N976B terminals accept standard tin-lead or RoHS-compliant matte-tin soldering per MIL-STD-750 Method 2026, supporting 260°C for 10 seconds.

How does the temperature coefficient of the 1N976B affect its regulation stability?

With a +0.095 %/°C temperature coefficient, the 1N976B's Zener voltage increases predictably with rising temperature-approximately +40.85 mV/°C at 43 V. This linear drift enables straightforward compensation in precision circuits. The 1N976B's coefficient is specified and validated across its full -65°C to +175°C operating range, ensuring consistent behavior in thermal cycling environments.

What is the maximum steady-state power dissipation for the 1N976B?

The 1N976B is rated for 500 mW steady-state power dissipation at lead temperature <50°C (measured 3/8 inch from body), de-rating linearly to zero at 175°C. When mounted on FR4 with 4 mm² copper pads, its usable power drops to 480 mW at 25°C ambient. The 1N976B's 8.8 mA I_ZM reflects this derated limit at 75°C lead temperature, not the full 500 mW.

Is the 1N976B suitable for high-reliability or radiation-exposed applications?

Yes-the 1N976B is inherently radiation-hardened per Microsemi MicroNote 050 and qualified to MIL-STD-750 Method 1020 for ESD insensitivity. Its hermetic DO-35 glass package and metallurgical construction make it suitable for aerospace, defense, and downhole industrial applications. The 1N976B's qualification data and radiation response are documented separately from commercial Zener families.