Microchip Technology 1N5235A

Overview

1N5235A from Microsemi is a 500 mW, 6.8 V ±10% glass axial-lead Zener diode in DO-35 (DO-204AH) package, designed for precision voltage regulation in low-power analog circuits, reference supplies, and overvoltage protection. It delivers 5.0 Ω dynamic impedance at 20 mA test current, operates from –65°C to +175°C, and features a +0.050 %/°C temperature coefficient.

For engineers reviewing the 1N5235A datasheet, 1N5235A pinout, 1N5235A application, or 1N5235A equivalent, key selection factors include its 6.8 V nominal Zener voltage, 10% tolerance (A suffix), 500 mW power rating at 25°C, DO-35 mechanical compatibility, and thermal resistance of 250 °C/W junction-to-lead.

Technical Context

The 1N5235A operates as a reverse-biased silicon Zener diode with sharp breakdown knee, validated by dual-point Zener impedance measurement per MicroNote 202. Its regulation stability relies on controlled dopant profiles and hermetically sealed glass construction.

It exhibits minimal capacitance (typical <2 pF at 0 V, per Figure 2), low forward voltage (≤1.5 V @ 200 mA), and radiation-hardened behavior per MicroNote 050 - making it suitable for high-reliability industrial and aerospace environments where ESD immunity (MIL-STD-750 Method 1020) and wide temperature operation are critical.

Key Specifications

Pinout & Package

Hermetically sealed axial-lead DO-35 (DO-204AH) glass package with cathode band marking; tin-lead or RoHS-compliant matte-tin plating; 0.2 g weight; 3/8″ (10 mm) lead length standard for thermal resistance specification.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N4734A and BZX55C6V8, the 1N5235A offers the best balance of DO-35 footprint compatibility, 20 mA-rated dynamic impedance, and military-grade screening options - making it ideal for space-constrained, high-reliability designs where exact legacy form factor and proven field performance are mandatory.

Availability

1N5235A is available at Aetrix Electronics and suitable for low-power voltage reference, overvoltage protection, and legacy power supply regulation requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for 1N5235A 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 aerospace, defense, and industrial markets.

The 1N52xxA/B series was designed for ruggedized, through-hole Zener regulation in mission-critical systems where long-term parametric stability, wide temperature operation, and JEDEC-standard mechanical compatibility are essential.

FAQ

What is the nominal Zener voltage and tolerance of the 1N5235A?

The 1N5235A has a nominal Zener voltage of 6.8 V with a ±10% tolerance, as indicated by the "A" suffix per Microsemi's documentation. This tolerance applies under standard test conditions (IZT = 20 mA, TA = 25°C) and is guaranteed across the full operating temperature range of –65°C to +175°C. The 1N5235A is not rated for tighter tolerances like ±5% (B suffix) or ±1% (D suffix).

What package type does the 1N5235A use, and how is polarity marked?

The 1N5235A uses the DO-35 (also designated DO-204AH) hermetically sealed glass axial-lead package. Polarity is marked by a single cathode band near one end of the glass body; the banded end is the cathode and must be held at a higher potential than the anode (non-banded end) for proper Zener regulation. This marking aligns with JEDEC standards for 1N52xx devices.

What is the maximum power dissipation of the 1N5235A, and how does it derate with temperature?

The 1N5235A has a maximum power dissipation of 500 mW at 25°C case temperature (TL). Derating follows a linear curve: power drops to zero at 175°C. At 100°C TL, the allowable dissipation is approximately 375 mW. This derating is defined with 3/8″ (10 mm) lead length from the body and assumes no PCB copper heatsinking - unlike surface-mount equivalents, the 1N5235A relies primarily on lead conduction for thermal management.

Does the 1N5235A support military-grade screening, and what prefixes indicate compliance?

Yes, the 1N5235A supports military-grade screening when ordered with appropriate prefixes and the "-1" suffix (e.g., MV1N5235A for JANTXV level). Per Microsemi's Features section, prefixes MQ (JAN), MX (JANTX), MV (JANTXV), and MSP (JANS) can be added to part numbers ending in "-1" to meet MIL-PRF-19500 requirements. Standard 1N5235A without prefix or "-1" is commercial-grade.

How does the temperature coefficient of the 1N5235A affect its regulation accuracy across temperature?

The 1N5235A has a positive temperature coefficient of +0.050 %/°C, meaning its Zener voltage increases by 0.050% per degree Celsius rise in junction temperature. Over a 100°C span (e.g., 25°C to 125°C), this results in ~34 mV total drift (0.050% × 6.8 V × 100). This predictable drift enables passive compensation in precision bias networks - a key advantage over lower-voltage Zeners with negative coefficients in the same family.