Microchip Technology 1N967B

Overview

1N967B from Microsemi is a silicon 500 mW axial-lead Zener diode in DO-35 (DO-204AH) package, rated for 18 V nominal Zener voltage at 7.0 mA test current, with ±5% tolerance (B suffix), 750 Ω dynamic impedance at I_ZT, and +0.085 %/°C temperature coefficient. It regulates voltage in low-power reference and protection circuits across industrial control and instrumentation systems.

For engineers reviewing the 1N967B datasheet, 1N967B pinout, 1N967B application, or 1N967B equivalent, key selection factors include its 18 V regulation point, 750 Ω Zener impedance at 7 mA, -65°C to +175°C operating range, DO-35 mechanical compatibility, and RoHS-compliant e3 variant availability.

Technical Context

The 1N967B operates as a two-terminal voltage reference device, conducting in reverse breakdown to maintain stable 18 V across its terminals within specified current limits (I_ZK = 0.25 mA min, I_ZM = 20 mA max). Its Zener knee is sharp, verified by dual-point impedance measurement per MicroNote 202.

Thermal design relies on junction-to-lead resistance of 250 °C/W (3/8″ lead length) and junction-to-ambient resistance of 310 °C/W on FR4 board; power derating begins above 50 °C lead temperature. Forward voltage is ≤1.1 V at 200 mA, confirming standard silicon PN junction behavior.

Key Specifications

Pinout & Package

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

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N967B, the BZX55C18 offers lower Zener impedance for improved line regulation, while the 1N4742A provides higher power handling at a different voltage - neither is pin-compatible nor drop-in; both require validation of thermal and electrical margins in the target design.

Availability

1N967B is available at Aetrix Electronics and suitable for industrial power supply reference, overvoltage protection clamp, test equipment calibration standard, and aerospace sensor biasing requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for 1N967B 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 analog, RF, and radiation-hardened components for defense, aerospace, and industrial markets.

The 1N967B belongs to Microsemi's legacy JEDEC-registered 1N957B–1N992B Zener series, designed specifically for ruggedized voltage regulation in harsh-environment applications demanding wide temperature operation and proven field reliability.

FAQ

What is the nominal Zener voltage and test current for the 1N967B?

The 1N967B has a nominal Zener voltage of 18 V measured at a test current (I_ZT) of 7.0 mA. This value is guaranteed within ±5% tolerance at 25°C per JEDEC registration. The device maintains regulation across a wide current range, from 0.25 mA (I_ZK) up to 20 mA (I_ZM), making it suitable for both precision reference and clamping roles in the 1N967B application space.

Does the 1N967B have RoHS-compliant variants?

Yes, the 1N967B is available in RoHS-compliant form with the "e3" suffix (e.g., 1N967Be3), featuring annealed matte-tin plating that meets EU Directive 2011/65/EU. This variant retains identical electrical specifications, thermal ratings, and DO-35 mechanical dimensions as the standard Sn/Pb version, enabling direct substitution in lead-free assembly processes without redesign.

What is the maximum power dissipation for the 1N967B under typical PCB mounting conditions?

The 1N967B delivers 480 mW maximum steady-state power when mounted on an FR4 PCB with 1 oz copper, 4 mm² pads, and 1 mm × 25 mm traces - derated linearly above 25°C ambient. At 3/8″ lead length from body, it sustains 500 mW up to 50°C lead temperature. Exceeding these limits risks thermal runaway; actual safe dissipation depends on layout and airflow, as defined in the 1N967B thermal resistance spec (310 °C/W junction-to-ambient).

How does the temperature coefficient affect the 1N967B's regulation accuracy over temperature?

The 1N967B has a temperature coefficient of +0.085 %/°C, meaning its Zener voltage increases by approximately 15.3 mV per °C rise near 18 V. Over a -65°C to +175°C range, this contributes up to ±2.0 V drift relative to 25°C baseline. For high-accuracy 1N967B applications, this must be combined with initial ±5% tolerance and thermal design to meet system-level voltage stability requirements.

Can the 1N967B replace the 1N4742A in a circuit?

No, the 1N967B cannot directly replace the 1N4742A. The 1N4742A is a 12 V, 1 W Zener in DO-41 package, whereas the 1N967B is 18 V, 0.5 W in DO-35. Voltage mismatch, power rating difference, and incompatible footprints make them functionally and mechanically non-interchangeable. Circuit redesign - including resistor recalculations and layout changes - would be required to substitute 1N967B for 1N4742A or vice versa.