Microchip Technology 1N992B

Overview

1N992B from Microsemi is a silicon 500 mW axial-leaded Zener diode in DO-35 (DO-204AH) package, rated for 200 V nominal Zener voltage with ±5% tolerance (B suffix), 0.65 mA Zener test current, and +0.11 %/°C temperature coefficient. It operates from –65°C to +175°C and regulates voltage in power supply reference and overvoltage protection circuits.

For engineers reviewing the 1N992B datasheet, 1N992B pinout, 1N992B application, or 1N992B equivalent, this part serves as a stable, glass-encapsulated, JEDEC-registered voltage reference with verified thermal resistance (310 °C/W on FR4), low reverse leakage (5 μA at 152 V), and RoHS-compliant variants available via "e3" suffix.

Technical Context

The 1N992B functions as a two-terminal voltage reference device operating in reverse breakdown mode. Its Zener voltage is specified at 200 V ±5% under 0.65 mA test current, with dynamic impedance of 8000 Ω at I_ZT and 2500 Ω at knee current (I_ZK = 0.25 mA).

It exhibits a positive temperature coefficient (+0.11 %/°C), indicating increasing V_Z with rising junction temperature. Maximum DC Zener current is 1.8 mA, and surge current rating is 9 A for 1/120 sec pulses - consistent with its 500 mW steady-state power limit derated above 50°C lead temperature.

Key Specifications

Pinout & Package

Package: DO-35 (DO-204AH), hermetically sealed axial-leaded glass body, cathode indicated by band. Tin-lead or RoHS-compliant matte-tin plating, weight 0.2 g.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N992B, 1N992BR offers enhanced mechanical and radiation robustness for mission-critical systems, while MMBZ5267B trades power handling and packaging integrity for miniaturization - making 1N992B optimal for high-stability, through-hole, high-voltage reference roles.

Availability

1N992B is available at Aetrix Electronics and suitable for high-voltage power supply reference, overvoltage protection clamp, and aerospace voltage monitor reference requiring stable component supply and long-lifecycle support.

Supply support for 1N992B 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 1N957B–1N992B series was designed specifically as JEDEC-standardized, glass-encapsulated Zener regulators delivering stable voltage references from 6.8 V to 200 V in harsh thermal and radiation environments.

FAQ

What is the Zener voltage tolerance for 1N992B?

The 1N992B has a nominal Zener voltage of 200 V with a ±5% tolerance, as indicated by the "B" suffix per JEDEC standard. This means the actual measured V_Z falls between 190 V and 210 V at 0.65 mA test current and 25°C. The tolerance is guaranteed across the full operating temperature range of –65°C to +175°C, supported by its +0.11 %/°C temperature coefficient.

Can 1N992B be used in surface-mount designs?

No - the 1N992B is exclusively packaged in the axial-leaded DO-35 (DO-204AH) glass case and is not a surface-mount device. For SMT equivalents, Microsemi offers the MLL992B in DO-213AA (MELF) package. Substituting 1N992B into an SMT footprint would require mechanical adaptation and invalidate thermal and reliability specifications.

What is the maximum surge current rating for 1N992B?

The 1N992B has a maximum surge current (I_ZSM) rating of 9 A for a 1/120 second duration square-wave or half-sine pulse. This value is derived from its 500 mW power rating and thermal mass, and is validated per Microsemi's test methodology. Exceeding this rating risks irreversible junction damage even if average power remains within limits.

Does 1N992B meet RoHS requirements?

The base 1N992B is not RoHS-compliant due to its standard tin-lead plating. However, the RoHS-compliant version is designated 1N992Be3, which substitutes annealed matte-tin plating and meets EU Directive 2011/65/EU. Both share identical electrical specs; only the termination material differs - confirmed in Microsemi's REV C datasheet.

How does the temperature coefficient affect 1N992B performance in a 100°C ambient design?

With a +0.11 %/°C temperature coefficient, the 1N992B's Zener voltage increases by approximately 2.2 V over a 100°C rise from 25°C (200 V × 0.11% × 75°C ≈ +1.65 V). At 100°C ambient, expected V_Z is ~201.7 V - well within its ±5% window. This predictable drift enables passive compensation in precision references.