onsemi 1N963B_T50A

Overview

1N963B_T50A from Fairchild Semiconductor is a 12 V, 5% tolerance, 500 mW glass-encapsulated Zener diode in DO-35 package, designed for precision voltage regulation and reference applications in power supply feedback loops, overvoltage protection circuits, and analog signal conditioning. It exhibits 10.5 Ω dynamic impedance at 11.5 mA test current and operates across –65°C to +200°C.

For engineers reviewing the 1N963B_T50A datasheet, pinout, applications, or equivalent options, key selection criteria include zener voltage accuracy (11.4–12.6 V), low dynamic impedance, thermal stability, and DO-35 mechanical compatibility with through-hole PCB layouts.

Technical Context

The 1N963B_T50A functions as a two-terminal voltage reference device, maintaining stable reverse-bias breakdown at nominal 12 V under controlled current conditions. Its operation relies on avalanche and Zener mechanisms depending on voltage level, with specified test current I_Z = 11.5 mA and maximum zener current I_ZM = 5 mA at rated power.

It features a 5% voltage tolerance, 10.5 Ω zener impedance (Z_Z) measured at 11.5 mA, and 0.25 μA maximum reverse leakage (I_R) at 9.1 V. The device is rated for 500 mW power dissipation at lead temperature ≤75°C with 4.0 mW/°C derating above that point.

Key Specifications

Pinout & Package

DO-35 glass axial package with cathode indicated by color band; two-terminal device with no internal polarity-sensitive logic or control pins.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N4742A and BZX55C12, the 1N963B_T50A offers superior regulation stiffness (10.5 Ω) in the industry-standard DO-35 form factor, making it optimal for compact, high-stability voltage reference designs requiring minimal layout change.

Availability

1N963B_T50A is available at Aetrix Electronics and suitable for switch-mode power supplies, overvoltage protection circuits, and industrial sensor interfaces requiring stable component supply and long-lifecycle support.

Supply support for 1N963B_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 semiconductor company specializing in power management, analog, and discrete components before its acquisition by ON Semiconductor in 2016.

The 1N957B–1N979B series was developed for general-purpose precision voltage regulation, targeting cost-effective, thermally robust Zener references in industrial and power conversion systems.

FAQ

What is the nominal zener voltage of the 1N963B_T50A?

The nominal zener voltage of the 1N963B_T50A is 12.0 V, with a guaranteed range of 11.4 V (minimum) to 12.6 V (maximum) at 11.5 mA test current and 25°C ambient. This value is defined per Fairchild's 1N957B–1N979B datasheet Rev. F1 and reflects the device's primary function as a precision 12 V shunt reference. The 1N963B_T50A achieves this specification using a glass-encapsulated DO-35 structure optimized for thermal stability.

What is the maximum power dissipation rating for the 1N963B_T50A?

The 1N963B_T50A has a maximum power dissipation of 500 mW at lead temperature (T_L) ≤ 75°C with 3/8″ lead length. Above 75°C, it derates linearly at 4.0 mW/°C. This rating applies specifically to the DO-35 package under standard mounting conditions and defines the upper thermal operating limit for continuous DC or pulsed operation. Exceeding this limit risks permanent degradation of the 1N963B_T50A's voltage regulation performance.

Does the 1N963B_T50A have a specified zener impedance, and what does it mean for circuit design?

Yes, the 1N963B_T50A has a specified zener impedance (Z_Z) of 10.5 Ω measured at 11.5 mA DC current. This parameter quantifies how tightly the device maintains its zener voltage under varying current conditions - lower impedance means better regulation against load or line transients. In practice, this allows the 1N963B_T50A to deliver stable reference voltage in feedback networks where current may fluctuate, directly improving the accuracy of systems relying on the 1N963B_T50A as a voltage基准.

What is the operating temperature range of the 1N963B_T50A?

The 1N963B_T50A is rated for an operating and storage temperature range of –65°C to +200°C. This wide range is enabled by its hermetically sealed DO-35 glass package and silicon die construction, making it suitable for under-hood automotive, industrial motor drives, and downhole instrumentation where extreme thermal cycling occurs. The 1N963B_T50A maintains its 12 V regulation specification across this full range, though voltage drift versus temperature must be evaluated per application requirements.

How is the cathode identified on the 1N963B_T50A package?

The cathode of the 1N963B_T50A is identified by a distinct color band on the DO-35 glass body, consistent with industry-standard marking for axial Zener diodes. This band corresponds to the cathode terminal, which must be connected to the higher-potential node in shunt regulation or clamping configurations. The 1N963B_T50A's top-marking format follows Fairchild's convention: first line is the F logo, second line reads "63", third line reads "B", confirming its identity as part of the 1N963B variant.