Microchip Technology 1N5275B

Overview

1N5275B from Microsemi is a 500 mW, 140 V ±5% glass axial-lead Zener diode in DO-35 (DO-204AH) package, designed for precision voltage regulation in low-power analog reference and overvoltage protection circuits. It delivers stable regulation at 20 mA test current with 1300 Ω dynamic impedance and operates across –65°C to +175°C.

For engineers reviewing the 1N5275B datasheet, 1N5275B pinout, 1N5275B application, or 1N5275B equivalent, key selection criteria include its 140 V nominal Zener voltage, ±5% tolerance (B suffix), 500 mW power rating, DO-35 mechanical form factor, and temperature coefficient of +0.110 %/°C - all critical for high-temperature industrial sensing and legacy power supply feedback loops.

Technical Context

This device functions as a two-terminal shunt voltage regulator, operating in reverse breakdown with cathode band indicating polarity. Its regulation performance is specified at IZT = 20 mA and validated over full military temperature range (–65°C to +175°C), with thermal resistance of 250 °C/W junction-to-lead at 3/8″ lead length.

The 1N5275B exhibits a sharp Zener knee due to guaranteed ZZT ≤ 1300 Ω at IZK = 0.25 mA and IR ≤ 0.1 μA at VR = 101 V, ensuring stable reference behavior under light-load conditions typical in sensor biasing and comparator threshold circuits.

Key Specifications

Pinout & Package

DO-35 (DO-204AH) hermetically sealed glass axial-leaded package with cathode identified by a single black band; leads are tin-lead or RoHS-compliant matte-tin plated, 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 1N5275B, 1N4744A serves entirely different voltage classes and cannot substitute directly, while BZX85C140 offers comparable voltage but lacks the 1N5275B's radiation hardness, military temperature range, and JEDEC registration - making it unsuitable for high-reliability deployments requiring MIL-PRF-19500 compliance.

Availability

1N5275B is available at Aetrix Electronics and suitable for industrial sensor reference, aerospace power monitoring, and high-temperature downhole instrumentation requiring stable component supply across extended lifecycle programs.

Supply support for 1N5275B 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, mixed-signal, and radiation-hardened components for defense, aerospace, and industrial markets.

The 1N52xxB series was engineered specifically for precision voltage regulation in mission-critical systems demanding extended temperature operation, radiation tolerance, and long-term parametric stability - particularly in legacy avionics and nuclear instrumentation.

FAQ

What is the nominal Zener voltage and tolerance of the 1N5275B?

The 1N5275B has a nominal Zener voltage of 140 V with a tolerance of ±5%, as indicated by the "B" suffix per JEDEC standard. This tolerance is guaranteed across the full operating temperature range of –65°C to +175°C, and the device is tested at 20 mA Zener test current (IZT) to ensure compliance. The 1N5275B is not rated for tighter tolerances like ±2% or ±1% - those require C or D suffix variants.

Does the 1N5275B support military-grade screening options?

Yes, the 1N5275B supports military screening per MIL-PRF-19500 when ordered with appropriate prefixes: MQ (JAN), MX (JANTX), MV (JANTXV), or MSP (JANS), always paired with the "-1" suffix for internal bond options. These versions retain the same 140 V Zener voltage and ±5% tolerance but add rigorous environmental testing, lot traceability, and extended reliability validation - essential for aerospace and defense applications where the 1N5275B is deployed.

What is the maximum power dissipation and thermal derating behavior of the 1N5275B?

The 1N5275B is rated for 500 mW at 25°C ambient, with linear derating to zero at 175°C. Its thermal resistance is 250 °C/W junction-to-lead at 3/8″ (10 mm) lead length from the glass body. When mounted on FR4 with 4 mm² copper pads, junction-to-ambient resistance rises to 310 °C/W, reducing usable power to 480 mW at 25°C. Derating curves are provided in Figure 1 of the official Microsemi datasheet for the 1N5275B.

How does the temperature coefficient affect the 1N5275B's regulation accuracy?

The 1N5275B has a positive temperature coefficient of +0.110 %/°C, meaning its Zener voltage increases by approximately 154 mV per 1°C rise above 25°C. At 125°C, this results in ~14.4 V increase - a total shift of ~10.3% from nominal. Designers must account for this drift in high-temperature applications; the 1N5275B's specification guarantees performance across the full –65°C to +175°C range, but absolute accuracy requires compensation or calibration if tight regulation is needed.

Is the 1N5275B RoHS compliant, and how is compliance indicated?

Yes, RoHS-compliant versions of the 1N5275B are available by adding the "e3" suffix (e.g., 1N5275Be3), indicating annealed matte-tin plating per J-STD-609. The base 1N5275B uses traditional tin-lead plating. Both versions share identical electrical and thermal specifications, including 140 V Zener voltage, ±5% tolerance, and DO-35 packaging. RoHS compliance is verified through material declarations and testing per EU Directive 2011/65/EU, and the 1N5275Be3 is fully compatible with lead-free reflow profiles up to 260°C for 10 seconds.