onsemi 1N966B_T50A

Overview

1N966B_T50A from Fairchild Semiconductor is a 5% tolerance, 16 V nominal Zener diode in DO-35 glass package, rated for 500 mW power dissipation at TL ≤ 75°C with 4.0 mW/°C derating, operating from –65°C to +200°C, and used for voltage regulation and reference in low-power analog circuits.

For engineers reviewing the 1N966B_T50A datasheet, pinout, applications, or equivalent options, key selection criteria include verified Zener voltage (15.2–16.8 V), dynamic impedance (19 Ω @ 7.8 mA), leakage current (0.25 μA @ 12.2 V), maximum Zener current (5 mA), and thermal stability across industrial temperature extremes.

Technical Context

The 1N966B_T50A functions as a precision voltage reference diode with sharp reverse-breakdown characteristics, designed for stable DC voltage clamping and biasing in linear power supplies, sensor excitation circuits, and overvoltage protection networks where tight voltage tolerance and low dynamic impedance are required.

It operates under controlled thermal conditions with lead-length-dependent power rating (3/8″), exhibits low leakage (<0.25 μA) at 80% of nominal Zener voltage, and maintains specified Zener impedance (19 Ω) only at its defined test current (7.8 mA), not across arbitrary bias points.

Key Specifications

Pinout & Package

DO-35 glass axial package with cathode indicated by color band; two-terminal device with no internal complexity - anode and cathode terminals only.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N966B_T50A, the 1N4744A offers higher power margin but requires PCB redesign, while the BZX55C16 matches package and voltage but trades 19 Ω impedance for lower leakage - selection depends on whether load regulation or bias current dominance governs the design.

Availability

1N966B_T50A is available at Aetrix Electronics and suitable for industrial power supply reference, automotive sensor biasing, and overvoltage clamp protection requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for 1N966B_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, signal conditioning, and discrete components before its acquisition by ON Semiconductor in 2016.

The 1N957B–1N979B family was engineered for general-purpose voltage regulation and reference applications demanding reliability, wide temperature operation, and consistent Zener performance in cost-constrained designs.

FAQ

What is the nominal Zener voltage of the 1N966B_T50A?

The 1N966B_T50A has a nominal Zener voltage of 16.0 V, with a guaranteed range of 15.2 V to 16.8 V at 7.8 mA test current and 25°C ambient. This value is measured under standardized thermal conditions (lead temperature = 30°C ± 1°C, 3/8″ lead length) per Fairchild's Rev. F1 datasheet. The 1N966B_T50A achieves this specification with 5% tolerance and is intended for use as a stable reference in regulated power supplies and precision bias networks.

Does the 1N966B_T50A have a specified Zener impedance, and at what current is it measured?

Yes, the 1N966B_T50A has a specified Zener impedance (Z_Z) of 19 Ω, measured at 7.8 mA DC test current with superimposed 0.1×IZ AC signal at 60 Hz. This impedance value reflects dynamic resistance in the breakdown region and directly impacts voltage regulation stability under varying load conditions. The 1N966B_T50A's low ZZ supports tight output tolerance in feedback loops and reference dividers where current ripple must translate to minimal voltage deviation.

What is the maximum power dissipation rating for the 1N966B_T50A, and how does it change with temperature?

The 1N966B_T50A is rated for 500 mW power dissipation at lead temperature (T_L) ≤ 75°C with 3/8″ lead length. Above 75°C, it derates linearly at 4.0 mW/°C - meaning at 100°C lead temperature, maximum allowable power drops to 400 mW. This derating curve is critical for thermal design in enclosed or high-ambient environments. The 1N966B_T50A's glass DO-35 package relies on lead conduction for heat transfer, so PCB layout and mounting directly affect real-world thermal performance.

What is the reverse leakage current specification for the 1N966B_T50A, and at what voltage is it tested?

The 1N966B_T50A specifies a maximum reverse leakage current (I_R) of 0.25 μA at 12.2 V - 80% of its nominal Zener voltage. This low leakage ensures minimal error contribution in high-impedance reference circuits, such as those used in precision sensor interfaces or battery-monitoring systems. The 1N966B_T50A maintains this specification across its full operating temperature range (–65°C to +200°C), making it suitable for applications where standby current must remain negligible over environmental extremes.

Is the 1N966B_T50A packaged in DO-35, and how is polarity marked?

Yes, the 1N966B_T50A uses the DO-35 glass axial package, with cathode polarity identified by a distinct color band near one end of the glass body. The anode is the unmarked lead. This marking convention is consistent across the 1N957B–1N979B family and aligns with JEDEC standards. The 1N966B_T50A's DO-35 form factor enables manual insertion and wave soldering while maintaining hermeticity and thermal stability required for industrial-grade Zener performance.