Microchip Technology 1N825A

Overview

1N825A from Microsemi is a temperature-compensated Zener reference diode with nominal 6.2 V output, ±5% tolerance, 19 Ω zener impedance at 7.5 mA, 0.002%/°C temperature coefficient, and DO-35 glass axial-leaded package. It delivers stable voltage reference in precision analog circuits operating from –65°C to +175°C.

For engineers reviewing the 1N825A datasheet, 1N825A pinout, 1N825A application, or 1N825A equivalent, this part supports high-stability DC biasing, instrumentation calibration, and military-grade voltage references where low TC and hermetic reliability are critical.

Technical Context

This device is a two-terminal, silicon-based Zener diode engineered for minimal voltage drift across temperature. Its temperature compensation achieves an effective TC of 0.002%/°C by balancing the positive TC of the Zener region with the negative TC of a series-connected forward-biased junction.

It operates optimally at 7.5 mA test current, delivering 5.9–6.5 V output with ≤19 Ω dynamic impedance and ≤2.0 µA reverse leakage at 3 V. The DO-35 hermetically sealed glass package ensures robustness in harsh environments including aerospace and defense systems.

Key Specifications

Pinout & Package

DO-35 glass axial-leaded package: cylindrical hermetic glass body with two radial leads; cathode identified by band marking; polarity requires banded end to be positive relative to unbanded end during operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N825 and 1N827A, the 1N825A delivers a verified 0.002%/°C TC and 19 Ω impedance - making it the preferred choice for aerospace telemetry, calibrated test equipment, and industrial controllers requiring guaranteed stability without over-spec'ing.

Availability

1N825A is available at Aetrix Electronics and suitable for high-reliability analog reference design, military instrumentation, and aerospace power monitoring requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for 1N825A 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 and mixed-signal components for aerospace, defense, and industrial markets.

The 1N821–1N829A series was designed specifically for precision voltage reference applications demanding hermetic packaging, extreme temperature resilience, and ultra-low temperature coefficients - especially in mission-critical systems.

FAQ

What is the nominal Zener voltage of the 1N825A?

The 1N825A has a nominal Zener voltage of 6.2 V, with a specified range of 5.9–6.5 V at 7.5 mA test current. This center value of 6.15 V allows for tighter tolerance versions (e.g., ±1%) via suffix notation like 1N825A-1%. The voltage is measured 15 seconds after applying DC current to ensure thermal stabilization.

What is the temperature coefficient of the 1N825A and how is it achieved?

The 1N825A exhibits an effective temperature coefficient of 0.002%/°C over –55°C to +100°C. This is achieved through internal temperature compensation - combining a Zener junction with a forward-biased junction whose opposing TCs cancel. The result is minimal voltage drift, validated per JEDEC registration and MIL-PRF-19500/159 test protocols.

Is the 1N825A available in military-grade versions?

Yes, the 1N825A qualifies for military-grade versions when ordered with the "-1" suffix (e.g., 1N825A-1) and appropriate prefixes: JAN, JANTX, or JANTXV. These variants meet MIL-PRF-19500/159 requirements and include internal metallurgical bonding for enhanced mechanical and thermal reliability in defense and space applications.

What package type does the 1N825A use and what are its key mechanical features?

The 1N825A uses the DO-35 (DO-204AH) hermetically sealed glass axial-leaded package. Key features include tin-lead plated solderable leads per MIL-STD-750 Method 2026, cathode identification via a band marking, and a weight of 0.2 grams. It supports soldering at 260°C for 10 seconds maximum and operates from –65°C to +175°C.

How does the 1N825A compare to the 1N825 in terms of voltage stability?

The 1N825A provides significantly better voltage stability than the 1N825 due to its lower temperature coefficient: 0.002%/°C versus 0.005%/°C. This translates to roughly half the voltage drift over temperature - a critical advantage in precision instrumentation and calibration systems where long-term repeatability is mandatory. Both share identical V_Z range and DO-35 packaging.