onsemi BZX55C13_T50R

Overview

BZX55C13_T50R from Fairchild Semiconductor is a 13 V ±5% tolerance silicon Zener diode in DO-35 glass package, rated for 500 mW power dissipation at TL ≤ 75°C, with 26 Ω dynamic impedance at 5 mA test current and 0.1 μA maximum reverse leakage at 10.4 V. It provides precise voltage regulation in low-power reference and protection circuits.

For engineers reviewing the BZX55C13_T50R datasheet, pinout, applications, or equivalent options, key selection criteria include zener voltage tolerance, thermal derating behavior, cathode identification via color band, DO-35 mechanical compatibility, and compliance with industrial temperature range (–65°C to +200°C).

Technical Context

The BZX55C13_T50R operates as a two-terminal voltage reference device, maintaining stable 13 V regulation under reverse bias when current exceeds the knee threshold. Its 26 Ω dynamic impedance ensures predictable voltage deviation across 1–10 mA operating range.

Thermal performance is defined by 4.0 mW/°C derating above 75°C lead temperature, with junction-to-ambient thermal resistance dependent on 3/8″ lead length mounting. The DO-35 glass package enables hermetic sealing and stable long-term V_Z drift.

Key Specifications

Pinout & Package

DO-35 glass axial package with cathode identified by single black color band. Leads are tinned copper-clad steel, 0.46 mm diameter, 25.4 mm minimum length. Hermetically sealed for moisture resistance and long-term parameter stability.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX55C13_T50R, the 1N4742A offers higher power but demands mechanical redesign, while the MMSZ4702 matches electrical specs in a surface-mount format-neither is drop-in, but both serve identical regulation functions in adapted layouts.

Availability

BZX55C13_T50R is available at Aetrix Electronics and suitable for automotive sensor references, industrial power supply clamps, and medical instrument calibration requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for BZX55C13_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

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 BZX55C series was developed as a general-purpose, cost-optimized Zener diode family targeting industrial and automotive voltage reference and protection applications with tight tolerance and robust thermal performance.

FAQ

What is the exact zener voltage range for BZX55C13_T50R at 25°C?

The BZX55C13_T50R has a specified zener voltage range of 12.4 V (minimum) to 14.1 V (maximum) at 5 mA test current and 25°C ambient temperature, reflecting its ±5% tolerance grade. This range is measured under thermal equilibrium conditions with 3/8″ lead length and 30°C ±1°C lead temperature, per Fairchild's test methodology documented in the BZX55C2V4–BZX55C56 datasheet Rev. D1.

Does BZX55C13_T50R have a cathode marking, and how is it identified?

Yes, BZX55C13_T50R uses a single black color band on the DO-35 glass body to denote the cathode terminal. This marking aligns with JEDEC standards and Fairchild's top-marking specification, where the band is positioned adjacent to the cathode lead. The anode is the unmarked lead, and polarity must be observed during PCB placement to ensure proper reverse-bias operation in regulation or clamping circuits.

What is the maximum allowable reverse current before breakdown in BZX55C13_T50R?

The BZX55C13_T50R exhibits a maximum reverse leakage current of 0.1 μA at VR = 10.4 V (90% of nominal VZ), measured at 25°C. This value remains stable up to 125°C, where IR increases to 2 μA - confirming its suitability for low-power bias networks where standby current must remain below 1 μA in battery-operated systems using the BZX55C13_T50R.

Can BZX55C13_T50R be used in surface-mount designs?

No, BZX55C13_T50R is manufactured exclusively in the DO-35 axial glass package and is not available in surface-mount variants. For SMT implementation, designers should consider functionally equivalent parts such as the MMSZ4702 (13 V, SOD-123) or BZX84-C13 (13 V, SOT-23), which share the same electrical specifications but require footprint and assembly process changes versus the through-hole BZX55C13_T50R.

How does thermal derating affect BZX55C13_T50R's power handling above 75°C?

BZX55C13_T50R's power dissipation must be linearly derated at 4.0 mW/°C above a lead temperature of 75°C. At 100°C lead temperature, its usable power drops to 400 mW (500 mW − [25°C × 4.0 mW/°C]). This derating curve is defined for 3/8″ lead length and must be applied in thermally constrained enclosures or high-ambient environments to prevent junction overheating and parametric shift in the BZX55C13_T50R.