onsemi 1N755A_T50A

Overview

1N755A_T50A from Fairchild Semiconductor is a 7.5V ±5% silicon Zener diode in DO-35 glass package, rated for 500mW power dissipation at TL ≤ 75°C, with 6Ω dynamic impedance at 20mA and 0.1µA reverse leakage at 1V, used for precision voltage regulation and reference in low-power analog circuits.

For engineers reviewing the 1N755A_T50A datasheet, pinout, applications, or equivalent options, key selection criteria include zener voltage tolerance, thermal derating behavior, cathode-band polarity marking, and DO-35 lead-form compatibility with through-hole PCB layouts.

Technical Context

This device operates as a two-terminal voltage reference diode, relying on controlled reverse-biased avalanche breakdown. Its 7.5V nominal zener voltage is specified at 20mA test current with ±5% tolerance, and its 6Ω dynamic impedance (ZZ) ensures stable regulation under small-signal load variations.

The DO-35 glass package supports operation from –65°C to +200°C, with power derating starting at 75°C (4.0mW/°C), and reverse leakage remains ≤0.1µA at VR = 1V across temperature extremes.

Key Specifications

Pinout & Package

DO-35 glass package: axial leads, cathode identified by color band; no polarity-sensitive internal structure beyond anode/cathode terminals.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N755A_T50A, 1N4734A offers higher power capacity but larger DO-41 packaging, while BZX55-C7V5 matches DO-35 form factor and enables tighter voltage accuracy-both require validation of thermal design and board space constraints.

Availability

1N755A_T50A is available at Aetrix Electronics and suitable for power supply regulation, sensor signal conditioning, industrial current loop protection, and automotive body control module designs requiring stable component supply and long-term obsolescence management.

Supply support for 1N755A_T50A 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

Fairchild Semiconductor was a U.S.-based designer and manufacturer of analog and discrete semiconductors, acquired by ON Semiconductor in 2016; known for robust, industry-standard diodes and power devices.

The 1N7xxA series was developed as a general-purpose, cost-optimized Zener family for voltage reference and regulation in consumer, industrial, and automotive electronics where DO-35 compatibility and ±5% tolerance meet system requirements.

FAQ

What is the nominal zener voltage and tolerance of the 1N755A_T50A?

The 1N755A_T50A has a nominal zener voltage of 7.5V with a ±5% tolerance, meaning its actual breakdown voltage falls between 7.13V and 7.88V when tested at 20mA. This tolerance is guaranteed at 25°C and applies across the full operating temperature range, making it suitable for non-critical reference applications where moderate accuracy suffices. The 1N755A_T50A achieves this specification using silicon planar junction technology in a DO-35 glass package.

What is the maximum power dissipation and thermal derating behavior of the 1N755A_T50A?

The 1N755A_T50A is rated for 500mW maximum power dissipation at lead temperature (TL) ≤ 75°C with 3/8″ lead length. Above 75°C, it derates linearly at 4.0mW/°C until reaching zero dissipation at 200°C. This behavior is defined by its DO-35 glass package thermal characteristics and must be accounted for in PCB layout-especially in enclosed or high-ambient environments. The 1N755A_T50A datasheet provides full derating curves for precise thermal design.

How is polarity marked on the 1N755A_T50A, and what is its forward voltage?

The 1N755A_T50A uses a cathode band (typically black or dark stripe) on the DO-35 glass body to identify the cathode terminal; the unmarked end is the anode. Its forward voltage is specified as ≤1.5V at 200mA forward current, consistent with standard silicon diode behavior. This forward characteristic allows the 1N755A_T50A to also serve as a basic rectifier in low-current paths, though its primary function remains reverse-bias voltage regulation.

What is the dynamic impedance and reverse leakage of the 1N755A_T50A, and why do they matter?

The 1N755A_T50A exhibits 6Ω dynamic impedance (ZZ) at 20mA and ≤0.1µA reverse leakage current (IR) at VR = 1V. Low ZZ ensures minimal output voltage variation under changing load currents-critical for stable biasing in amplifiers or ADC references. Ultra-low IR prevents loading errors in high-impedance circuits like sensor bridges or battery monitors. These parameters directly define the 1N755A_T50A's performance as a precision shunt regulator.

Is the 1N755A_T50A suitable for automotive applications, and what temperature range does it support?

Yes, the 1N755A_T50A supports operation from –65°C to +200°C junction temperature, making it suitable for under-hood and body-control automotive applications where extended thermal range is required. Its DO-35 glass construction and silicon junction provide proven reliability in cyclic thermal stress environments. While not AEC-Q200 qualified out-of-box, the 1N755A_T50A has been widely deployed in automotive subsystems meeting legacy OEM requirements-and remains a validated choice in many production ECUs.