onsemi 1N5243B_T50A

Overview

1N5243B_T50A from ON Semiconductor is a 13 V, ±5% tolerance, 500 mW DO-35 glass-encapsulated Zener diode optimized for precision voltage regulation in low-power analog and reference circuits. It delivers 13.65 V maximum Zener voltage at 9.5 mA test current, with 13 Ω dynamic impedance and 0.5 μA reverse leakage at 10.4 V, enabling stable biasing in sensor signal conditioning and power supply feedback paths.

For engineers reviewing the 1N5243B_T50A datasheet, pinout, applications, or equivalent options, key selection criteria include Zener voltage accuracy, temperature coefficient (±0.079 %/°C), low leakage at rated VR, thermal stability in DO-35 package, and compatibility with through-hole PCB layouts requiring hermetic glass sealing.

Technical Context

This device operates as a two-terminal shunt regulator, maintaining a stable reverse-biased breakdown voltage across its anode–cathode terminals. Its DO-35 glass package provides hermetic sealing and thermal resistance of 250°C/W, supporting operation from −65°C to +200°C junction temperature.

The 1N5243B_T50A exhibits a nominal Zener voltage of 13 V with tight 5% tolerance, measured at I_Z = 9.5 mA, and features a positive temperature coefficient (+0.079 %/°C) - critical for compensating drift in voltage references where ambient variation exceeds ±10°C.

Key Specifications

Pinout & Package

DO-35 glass axial package: hermetically sealed, 2.0 mm diameter × 4.56 mm length, cathode indicated by color band on body. Anode and cathode leads are unmarked but electrically symmetric except for polarity marking.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N4742A and BZX55C13, the 1N5243B_T50A offers superior thermal predictability (+0.079 %/°C) and lower Z_Z than BZX55C13, while matching the DO-35 form factor of both - making it optimal for space-constrained, temperature-stable reference designs.

Availability

1N5243B_T50A is available at Aetrix Electronics and suitable for industrial sensor signal conditioning, low-power microcontroller voltage reference, linear regulator feedback divider, and overvoltage clamp in 12 V automotive subsystems requiring stable component supply and long-lifecycle support.

Supply support for 1N5243B_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

ON Semiconductor is a global semiconductor manufacturer specializing in energy-efficient power, analog, sensing, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The 1N52xxB series belongs to ON Semiconductor's legacy Zener diode product line, designed specifically for precision voltage regulation in cost-sensitive, high-reliability through-hole applications demanding hermetic packaging and tight parametric control.

FAQ

What is the exact Zener voltage range for 1N5243B_T50A at 9.5 mA test current?

The 1N5243B_T50A has a specified Zener voltage range of 13.0 V minimum to 13.65 V maximum when tested at I_Z = 9.5 mA and T_A = 25°C. This 5% tolerance window is guaranteed per ON Semiconductor's Rev. 3 datasheet and applies to every unit shipped. The 1N5243B_T50A achieves this specification using process-controlled diffusion in a DO-35 glass package.

Does 1N5243B_T50A have a documented temperature coefficient, and how does it affect regulation accuracy?

Yes, the 1N5243B_T50A has a documented temperature coefficient of +0.079 %/°C, meaning its Zener voltage increases by approximately 10.3 mV per °C rise in junction temperature. This positive TC allows predictable compensation in multi-Zener reference strings and must be factored into total error budgets for applications operating beyond 25°C ambient. The 1N5243B_T50A's TC is measured and binned per datasheet Section 2.

Can 1N5243B_T50A replace 1N4742A in existing DO-41 footprints?

No - the 1N5243B_T50A uses a DO-35 package (2.0 mm diameter, 4.56 mm length), while the 1N4742A uses DO-41 (2.7 mm diameter, 5.2 mm length). Their lead spacing, body size, and thermal mass differ significantly. Direct replacement would require PCB redesign. The 1N5243B_T50A is not a drop-in substitute for 1N4742A, though both deliver 500 mW Zener regulation.

What is the maximum reverse leakage current for 1N5243B_T50A, and at what voltage is it specified?

The maximum reverse leakage current for 1N5243B_T50A is 0.5 μA, specified at V_R = 10.4 V and T_A = 25°C. This value is guaranteed per the Absolute Maximum Ratings table and reflects worst-case leakage under sub-breakdown conditions. At lower voltages (e.g., 5 V), leakage drops below 0.1 μA, making the 1N5243B_T50A suitable for ultra-low-power bias networks.

Is the DO-35 package of 1N5243B_T50A hermetically sealed, and why does that matter?

Yes, the DO-35 package of 1N5243B_T50A is hermetically sealed glass, as confirmed in the "General Requirements" section of the ON Semiconductor datasheet. This prevents moisture ingress and parameter drift over time - critical for long-life industrial and automotive applications where field reliability exceeds 10 years. Hermetic sealing distinguishes the 1N5243B_T50A from plastic-packaged Zeners like the 1N47xx series.