Microchip Technology 1N5951BUR-1/TR

Overview

1N5951BUR-1 from Microsemi is a 1.5 W surface-mount Zener diode in DO-213AB (MELF) glass package, rated for 120 V Zener voltage at 3.1 mA test current, with 380 Ω dynamic impedance, 1.0 µA reverse leakage at 91.2 V, and -65 °C to +175 °C junction temperature range. It serves as a precision voltage reference or shunt regulator in high-reliability power supply feedback loops.

For engineers reviewing the 1N5951BUR-1 datasheet, 1N5951BUR-1 pinout, 1N5951BUR-1 application, or 1N5951BUR-1 equivalent, key selection criteria include Zener voltage tolerance (±5%), hermetic glass packaging, MIL-PRF-19500 screening capability, low thermal resistance (40 °C/W junction-to-end-cap), and radiation-hardened performance per MicroNote 050.

Technical Context

This device operates as a shunt voltage regulator in reverse-biased breakdown mode, with Zener voltage specified at T_EC = 30 °C and stabilized 90 s after DC current application. Its metallurgically bonded tungsten slug construction ensures low thermal resistance and enhanced reliability under thermal cycling.

The DO-213AB MELF package provides hermetic sealing, ESD immunity per MIL-STD-750 Method 1020, and capacitance of ~2.5 pF (inferred from Figure 2 at 120 V), making it suitable for noise-sensitive regulation where parasitic capacitance must remain below 3 pF.

Key Specifications

Pinout & Package

DO-213AB (MELF) glass package: hermetically sealed voidless hard glass body with tungsten slugs; cathode indicated by single black band; lead-free matte tin plating over copper; weight ≈ 0.05 g; dimensions: BD = 2.39–2.67 mm, BL = 4.80–5.21 mm.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N5951B and SMBG5951B, the 1N5951BUR-1 uniquely combines hermetic MELF packaging, radiation tolerance, and lowest thermal resistance among 120 V Zener variants-making it the only choice for mission-critical SMT regulation where long-term parameter stability and extreme environment survivability are mandatory.

Availability

1N5951BUR-1 is available at Aetrix Electronics and suitable for industrial power supplies, aerospace telemetry systems, and downhole sensor modules requiring stable component supply with guaranteed long-term availability and traceable sourcing.

Supply support for 1N5951BUR-1 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) designs high-reliability analog and mixed-signal semiconductors for aerospace, defense, and industrial markets, with emphasis on radiation-hardened, high-temperature, and hermetically packaged components.

The 1N59xxBUR-1 series was developed to replace axial-leaded 1N59xxB diodes in surface-mount applications while preserving MIL-PRF-19500 qualification paths and enhancing thermal performance via metallurgically bonded MELF construction.

FAQ

What is the Zener voltage tolerance for 1N5951BUR-1?

The 1N5951BUR-1 has a nominal Zener voltage of 120 V with a tolerance of ±5%, as designated by the "B" suffix in its part nomenclature. This tolerance is verified at T_EC = 30 °C with 90-second stabilization after applying the 3.1 mA test current. The 1N5951BUR-1 maintains this tolerance across its full operating temperature range of -65 °C to +175 °C when used within derated power limits.

Is 1N5951BUR-1 RoHS compliant?

Yes, the 1N5951BUR-1 is RoHS compliant, indicated by the "e3" suffix in alternate nomenclature (e.g., 1N5951BUR-1(e3)). Its terminations use matte tin plating over copper, solderable per MIL-STD-750 Method 2026, and fully conform to EU Directive 2011/65/EU. The 1N5951BUR-1 meets lead-free reflow requirements up to 260 °C for 10 seconds.

Can 1N5951BUR-1 be used in radiation-intensive environments?

Yes, the 1N5951BUR-1 is inherently radiation-hardened per Microsemi MicroNote 050, with demonstrated functionality after total ionizing dose (TID) exposure exceeding 100 krad(Si). Its hermetic glass package and metallurgically bonded structure prevent parametric degradation under gamma irradiation, making the 1N5951BUR-1 suitable for satellite power systems and nuclear instrumentation.

What is the maximum reverse current for 1N5951BUR-1 at rated voltage?

The 1N5951BUR-1 specifies a maximum reverse leakage current (I_R) of 1.0 µA at a reverse voltage (V_R) of 91.2 V - 76% of its 120 V Zener voltage. This low leakage ensures minimal power loss in high-impedance reference circuits and preserves accuracy in battery-powered or energy-harvesting applications using the 1N5951BUR-1.

Does 1N5951BUR-1 require special PCB layout considerations?

Yes, the 1N5951BUR-1 uses a DO-213AB MELF package requiring symmetrical 7.0 mm × 1.8 mm pad layout per the manufacturer's recommended footprint. Thermal performance depends on maintaining ≥2.8 mm spacing between adjacent components to avoid end-cap heating; the 1N5951BUR-1 achieves optimal R_θJEC = 40 °C/W only when mounted per the specified pad geometry and copper area.