Microchip Technology 1N2998RB

Overview

1N2998RB from Microsemi is a 10 W, 52 V, ±5% tolerance Zener diode in DO-4 (DO-213AA) hermetically sealed metal-glass package with reverse polarity (anode-to-stud), qualified to MIL-PRF-19500/124 JANTXV level for high-reliability voltage regulation in power supply reference and overvoltage protection circuits.

For engineers reviewing the 1N2998RB datasheet, 1N2998RB pinout, 1N2998RB application, or 1N2998RB equivalent, this part delivers stable 52 V regulation at 15 mA test current, low 160 Ω dynamic impedance, and operation across –65 °C to +175 °C junction temperature - critical for aerospace, defense, and industrial systems requiring radiation-hardened, ESD-nonsensitive components.

Technical Context

This device operates as a precision voltage reference in the reverse breakdown region, with Zener voltage specified at I_ZT = 15 mA and thermal resistance R_θJC = 12 °C/W enabling 10 W dissipation at T_C = +55 °C. Its hermetically sealed DO-4 package ensures long-term stability under harsh environmental stress.

It exhibits a positive temperature coefficient of +0.090 %/°C and maximum reverse leakage of 10 µA at V_R = 39.0 V, supporting reliable regulation across wide current and temperature ranges without external compensation.

Key Specifications

Pinout & Package

Package: DO-4 (DO-213AA), hermetically sealed metal-glass stud-mount case with 10-32 UNF–2A threaded stud (anode terminal), weight ≈7.5 g. Mounting requires mechanical fastening to heatsink; polarity is reverse (anode-to-stud).

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N2998B and 1N5375B, the 1N2998RB uniquely combines reverse polarity, 10 W power handling, JANTXV qualification, and radiation tolerance - making it irreplaceable in deployed military platforms and space-qualified subsystems where form-fit-function and reliability certification are mandatory.

Availability

1N2998RB is available at Aetrix Electronics and suitable for avionics power reference, defense radar bias supply, and industrial motor drive protection requiring stable component supply with full MIL-PRF-19500/124 traceability and long-term obsolescence management.

Supply support for 1N2998RB 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 analog and mixed-signal ICs, discrete devices, and RF solutions for aerospace, defense, and industrial markets.

The 1N2998RB belongs to Microsemi's legacy MIL-qualified Zener diode family designed specifically for voltage regulation in safety-critical systems where hermeticity, radiation tolerance, and extended temperature operation are non-negotiable design requirements.

FAQ

What does the "RB" suffix mean in 1N2998RB?

The "RB" suffix in 1N2998RB indicates reverse polarity: the anode is connected to the threaded stud, and the cathode is the axial lead wire. This configuration differs from standard-polarity variants like 1N2998B (cathode-to-stud) and must be verified in mechanical mounting and circuit grounding schemes before integration. The 1N2998RB maintains identical electrical specs - including 52 V Zener voltage and 10 W rating - as its standard-polarity counterpart.

Is 1N2998RB qualified to MIL-PRF-19500/124, and what levels are available?

Yes, the 1N2998RB is qualified to MIL-PRF-19500/124 at JANTXV level - the highest reliability tier - with full screening including temperature cycling, burn-in, and parametric testing per military standards. JAN and JANTX versions are also available upon request. Commercial-grade equivalents lack this qualification and should not be substituted without requalification. The 1N2998RB data sheet explicitly lists JANTXV qualification in its description section.

What is the maximum reverse leakage current for 1N2998RB, and at what voltage is it measured?

The maximum reverse leakage current for 1N2998RB is 10 µA, measured at V_R = 39.0 V (75% of nominal 52 V Zener voltage). This value is guaranteed across the full operating temperature range and reflects the device's ability to maintain low standby power in precision bias networks. It is specified in the Electrical Characteristics table on page 4 of the T4-LDS-0075 datasheet and applies to all qualification levels including JANTXV.

Can 1N2998RB be mounted directly to a heatsink, and what is its thermal resistance?

Yes, the 1N2998RB is designed for direct stud-mounting to a heatsink via its 10-32 UNF–2A threaded metal case. Its thermal resistance from junction to case (R_θJC) is 12 °C/W, enabling full 10 W power dissipation at T_C = +55 °C. Mechanical torque must not exceed 15 inch-pounds to avoid thread damage. This thermal path is intrinsic to the DO-4 package and is validated in the Maximum Ratings table on page 1 of the 1N2998RB datasheet.

Does 1N2998RB have radiation hardness, and is it documented?

Yes, the 1N2998RB exhibits inherent radiation hardness as described in Microsemi MicroNote 050, which documents its performance after total ionizing dose exposure exceeding 100 krad(Si). This characteristic stems from its hermetically sealed metal-glass construction and is confirmed for the entire 1N2970B–1N3015B series. Radiation hardness is not a screened parameter but a material-level property verified in application notes - making the 1N2998RB suitable for low-earth orbit and nuclear instrumentation applications.