onsemi BZX55C2V7_T50R

Overview

BZX55C2V7_T50R from Fairchild Semiconductor is a 2.7 V ±5% tolerance silicon Zener diode in DO-35 glass package, rated for 500 mW power dissipation at 75°C lead temperature, with 85 Ω dynamic impedance at 5 mA test current and 50 μA reverse leakage at 1 V reverse voltage. It serves as a precision voltage reference or overvoltage clamp in low-power analog signal conditioning circuits.

For engineers reviewing the BZX55C2V7_T50R datasheet, pinout, applications, or equivalent options, key selection criteria include zener voltage tolerance, thermal derating behavior, dynamic impedance at nominal test current, reverse leakage at sub-zener bias, and DO-35 mechanical compatibility in space-constrained PCB layouts.

Technical Context

The BZX55C2V7_T50R operates as a two-terminal voltage-regulating device relying on controlled reverse-biased avalanche breakdown. Its 2.7 V nominal zener voltage is specified at 5 mA test current with ±5% tolerance and measured under thermal equilibrium at 30°C lead temperature with 3/8″ lead length.

It exhibits 85 Ω dynamic impedance (ZZ) at IZ = 5 mA, 50 μA reverse leakage (IR) at VR = 1 V, and supports maximum zener current (IZM) of 155 mA at 25°C - derating linearly by 4.0 mW/°C above 75°C ambient.

Key Specifications

Pinout & Package

DO-35 glass axial package with cathode indicated by color band; two-terminal device requiring no external biasing circuitry.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N5223B and MMSZ4678, the BZX55C2V7_T50R delivers matched 5 mA test-point impedance, DO-35 mechanical robustness for manual assembly, and full 500 mW rating at standard lead temperature - making it optimal for legacy through-hole designs requiring stable low-current regulation.

Availability

BZX55C2V7_T50R is available at Aetrix Electronics and suitable for temperature sensor biasing, microcontroller reset circuits, USB port overvoltage clamping, and industrial current loop interfaces requiring stable component supply across extended temperature ranges.

Supply support for BZX55C2V7_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 BZX55 series was developed for general-purpose voltage regulation and clamping in cost-sensitive industrial, automotive, and consumer electronics - emphasizing reliability, tight tolerance, and DO-35 manufacturability.

FAQ

What is the zener voltage tolerance of BZX55C2V7_T50R?

The BZX55C2V7_T50R has a guaranteed zener voltage range of 2.56 V to 2.90 V at 5 mA test current, corresponding to ±5% tolerance around the nominal 2.7 V rating. This tolerance is verified per Fairchild's BZX55C2V4–BZX55C56 specification and applies under thermal equilibrium conditions at 30°C lead temperature. The BZX55C2V7_T50R maintains this tolerance across its full operating temperature range without additional calibration.

How does thermal derating affect BZX55C2V7_T50R power handling?

The BZX55C2V7_T50R is rated for 500 mW power dissipation only when lead temperature (TL) remains at or below 75°C. Above that, it derates linearly at 4.0 mW/°C - meaning at TL = 100°C, maximum allowable power drops to 400 mW. This derating curve is defined in the Absolute Maximum Ratings table and must be applied using measured lead temperature, not ambient, due to the DO-35 package's thermal path dependency on lead length and PCB copper area.

What is the reverse leakage current specification for BZX55C2V7_T50R?

The BZX55C2V7_T50R specifies 50 μA maximum reverse leakage current (IR) at VR = 1 V, measured at 25°C. This value reflects off-state conduction well below the zener knee and is critical for low-power applications such as battery-backed sensors or always-on reset monitors. At elevated temperatures (e.g., 125°C), IR increases to 100 μA, as documented in the Electrical Characteristics table.

Can BZX55C2V7_T50R be used in forward-bias applications?

Yes, the BZX55C2V7_T50R functions as a standard silicon diode in forward bias, with forward voltage (VF) ≤1.3 V at IF = 100 mA. While not optimized for rectification, this characteristic allows dual-use in circuits requiring both low-voltage clamping and polarity protection - for example, in bidirectional signal line protectors where forward conduction limits negative excursions while reverse breakdown regulates positive surges.

Is BZX55C2V7_T50R suitable for automotive under-hood applications?

Yes, the BZX55C2V7_T50R supports an operating temperature range of –65°C to +200°C and is qualified for industrial-grade reliability. Its DO-35 glass package provides hermetic sealing against moisture and contaminants, and its electrical parameters remain stable across thermal cycling. While not AEC-Q200 certified as a standalone part, the BZX55C2V7_T50R has been deployed in non-safety-critical automotive subsystems including cabin climate control and body electronics where extended temperature operation is required.