Microchip Technology 1N2979RD

Overview

1N2979RD from Microsemi is a 10 W, 15 V Zener diode in DO-213AA (DO-4) hermetically sealed metal-glass stud package, rated for junction temperatures from –65 °C to +175 °C, with ±5% voltage tolerance and 170 Ω dynamic impedance at 3 mA test current - used for precision voltage regulation in high-reliability military power supplies and radiation-hardened instrumentation.

For engineers reviewing the 1N2979RD datasheet, 1N2979RD pinout, 1N2979RD application, or 1N2979RD equivalent, this part supports stable regulation under wide temperature swings, requires stud-mounting with 10–32 UNF hardware, complies with MIL-PRF-19500/124 JANTXV qualification, and delivers low leakage (<10 µA at 11.4 V) in harsh environments.

Technical Context

This device operates as a reverse-biased voltage reference with a nominal Zener voltage of 15 V at 3 mA (IZT), exhibiting +0.082%/°C temperature coefficient and 170 Ω dynamic impedance (ZZT) at IZT. Its hermetic DO-4 metal-glass construction ensures long-term stability under thermal cycling and humidity exposure.

Rated for 10 W steady-state dissipation at TC = +55 °C (derated linearly to zero at +175 °C), it supports maximum Zener current of 250 mA at 25 °C stud temperature and withstands solder reflow up to 260 °C for 10 seconds - confirming suitability for high-power, mission-critical analog regulation circuits.

Key Specifications

Pinout & Package

Package: DO-213AA (DO-4), hermetically sealed metal-glass stud package with 10–32 UNF–2A threads; weight ≈ 7.5 g; polarity: cathode-to-stud for 1N3993A–1N3998A series, but 1N2979RD belongs to 1N2970B–1N3015B series - standard polarity is anode-to-stud; "RD" suffix indicates JANTXV reliability level and reverse polarity (cathode-to-stud), per nomenclature on Page 2.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N2979B (commercial) and 1N3004B (91 V), the 1N2979RD uniquely combines 15 V regulation, JANTXV qualification, cathode-to-stud polarity, and verified radiation hardness - making it irreplaceable in flight-critical and nuclear-grade designs where parameter stability under stress is non-negotiable.

Availability

1N2979RD is available at Aetrix Electronics and suitable for avionics power regulation, nuclear instrumentation reference, and downhole telemetry supply requiring stable component supply across extended temperature and radiation environments.

Supply support for 1N2979RD 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 Corporation (now part of Microchip Technology) is a U.S.-based semiconductor company specializing in high-reliability, radiation-hardened, and aerospace-grade components.

The 1N2970B–1N3015B series was engineered for military and space applications demanding extreme environmental resilience, including full MIL-PRF-19500/124 qualification and proven performance under thermal, mechanical, and ionizing radiation stress.

FAQ

What is the Zener voltage tolerance and test condition for 1N2979RD?

The 1N2979RD has a nominal Zener voltage of 15 V with a guaranteed tolerance of ±5%, measured at a Zener test current (IZT) of 3 mA and case temperature of +25 °C. This tolerance remains valid across its full qualified operating temperature range from –65 °C to +175 °C, as confirmed in the Electrical Characteristics table on Page 4 of T4-LDS-0075 Rev. 3.

Does 1N2979RD have JANTXV qualification and what does the "RD" suffix mean?

Yes, the "RD" suffix in 1N2979RD explicitly denotes JANTXV reliability level and reverse polarity (cathode-to-stud), per the nomenclature guide on Page 2 of T4-LDS-0075 Rev. 3. It is fully qualified to MIL-PRF-19500/124, including extended screening for burn-in, thermal shock, and radiation hardness - distinguishing it from commercial or JAN-grade variants of the same voltage.

What is the maximum steady-state power dissipation for 1N2979RD and how does it derate with temperature?

The 1N2979RD is rated for 10 W steady-state power dissipation at case temperature (TC) = +55 °C, with linear derating of 0.083 W/°C above that point until reaching zero dissipation at +175 °C. This derating behavior is defined in the Maximum Ratings table on Page 1 and applies regardless of ambient or junction temperature, as thermal resistance (RθJC = 12 °C/W) anchors the relationship between stud temperature and power.

Is 1N2979RD RoHS compliant and what plating options are available?

No, 1N2979RD is not RoHS compliant. Per Page 2 of T4-LDS-0075 Rev. 3, the "e3" RoHS suffix is available only on commercial-grade parts; JANTXV-qualified devices like 1N2979RD use traditional tin-lead plating on nickel terminals. The datasheet confirms RoHS compliance is restricted to commercial versions and explicitly excludes JAN/JANTX/JANTXV grades.

What is the reverse leakage current specification for 1N2979RD and at what voltage is it tested?

The 1N2979RD exhibits a maximum reverse leakage current (IR) of 10 µA, tested at a reverse voltage (VR) of 11.4 V - which corresponds to 76% of its nominal 15 V Zener voltage. This value is specified in the Electrical Characteristics table on Page 4 and reflects worst-case leakage under regulation conditions before breakdown onset.