onsemi 1N5256B_T50R

Overview

1N5256B_T50R from ON Semiconductor is a 30 V ±5% Zener diode in DO-35 glass package, rated for 500 mW power dissipation at 25°C with 49 Ω dynamic impedance at 20 mA test current and 0.25 μA maximum reverse leakage at 23 V. It serves as a precision voltage reference or overvoltage clamp in low-power analog circuits, power supply feedback loops, and sensor signal conditioning stages.

For engineers reviewing the 1N5256B_T50R datasheet, pinout, applications, or equivalent options, key selection criteria include its 30 V nominal Zener voltage, tight 5% tolerance, DO-35 axial leaded package compatibility with through-hole PCB assembly, and thermal stability characterized by +0.09 %/°C temperature coefficient.

Technical Context

This device operates in reverse breakdown mode to maintain stable voltage across its terminals under varying load or input conditions. Its Zener voltage is specified at I_Z = 20 mA with thermal equilibrium at 30°C lead temperature, and it exhibits 49 Ω dynamic impedance (Z_Z) at that bias point.

The 1N5256B_T50R features a DO-35 hermetically sealed glass package with cathode band marking, supports 500 mW continuous power dissipation at 25°C, and derates linearly at 4.0 mW/°C above 50°C ambient - enabling reliable operation in industrial temperature ranges up to +200°C junction temperature.

Key Specifications

Pinout & Package

DO-35 glass axial package with cathode identified by a color band on one end; anode and cathode are unidirectional terminals with no internal complexity - only two terminals requiring correct polarity orientation during placement.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N5256B_T50R, 1N5256BRLG offers identical electrical behavior with packaging optimized for surface-mount assembly, while BZX55C30 trades tighter Z_Z and lower leakage for broader vendor availability at reduced cost - making it suitable for non-critical clamping but not precision reference roles.

Availability

1N5256B_T50R is available at Aetrix Electronics and suitable for industrial power supplies, sensor interface circuits, and microcontroller reset supervision requiring stable component supply with full traceability and long-lifecycle support.

Supply support for 1N5256B_T50R 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 supplier specializing in energy-efficient power management, analog, sensor, and logic solutions for automotive, industrial, and consumer markets.

The 1N52xxB series was designed as a general-purpose, high-reliability Zener diode family for voltage regulation and protection in cost-sensitive, high-volume applications across industrial and computing systems.

FAQ

What is the Zener voltage tolerance of the 1N5256B_T50R?

The 1N5256B_T50R has a Zener voltage tolerance of ±5%, meaning its nominal 30 V rating falls between 28.5 V and 31.5 V when measured at I_Z = 20 mA and thermal equilibrium at 30°C lead temperature. This tolerance is confirmed in the ON Semiconductor 1N5221B–1N5263B datasheet Rev. 3, Table on page 2. The 1N5256B_T50R meets this specification under standard test conditions and is not subject to wider variation unless operated outside recommended thermal limits.

Does the 1N5256B_T50R support high-temperature operation?

Yes, the 1N5256B_T50R is rated for an operating junction temperature range of −65°C to +200°C and storage temperature from −65°C to +200°C. Its power dissipation derates linearly at 4.0 mW/°C above 50°C ambient, allowing sustained operation up to +150°C case temperature with appropriate PCB copper area. This makes the 1N5256B_T50R suitable for under-hood automotive modules and industrial motor drive controls where thermal robustness is essential.

What is the forward voltage drop of the 1N5256B_T50R?

The forward voltage (V_F) of the 1N5256B_T50R is specified as ≤1.2 V at I_F = 200 mA, consistent with standard silicon PN junction characteristics. This value is documented in the "Electrical Characteristics" section of the ON Semiconductor datasheet. While the 1N5256B_T50R is primarily used in reverse breakdown, this forward characteristic ensures predictable behavior during transient overvoltage events or bidirectional clamping configurations involving the 1N5256B_T50R.

How is the cathode identified on the 1N5256B_T50R package?

The cathode of the 1N5256B_T50R is marked by a distinct color band on the DO-35 glass body - a standardized visual indicator per JEDEC DO-204AH. This band aligns with the cathode terminal, which must be connected to the higher-potential node in Zener regulation applications. The 1N5256B_T50R's marking follows ON Semiconductor's top-mark convention: first line is logo, second line reads "25", third line reads "6B", confirming identity and polarity without ambiguity.

Is the 1N5256B_T50R RoHS compliant?

Yes, the 1N5256B_T50R is RoHS compliant and meets the requirements of Directive 2011/65/EU, including restrictions on lead, mercury, cadmium, hexavalent chromium, PBB, and PBDE. Compliance is verified through ON Semiconductor's material declarations and applies to the DO-35 glass package and internal silicon die. This RoHS status is maintained across all manufacturing lots of the 1N5256B_T50R and is documented in ON Semiconductor's official product change notices and environmental reports.