onsemi BZX55C9V1_T50R

Overview

BZX55C9V1_T50R from Fairchild Semiconductor is a 9.1 V ±5% tolerance silicon Zener diode in DO-35 glass package, rated for 500 mW power dissipation at 75°C with 10 Ω dynamic impedance at 5 mA test current and 0.1 μA maximum reverse leakage at 7 V. It provides precise voltage regulation in low-power reference and protection circuits.

For engineers reviewing the BZX55C9V1_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 specified VR, and DO-35 mechanical compatibility in space-constrained analog designs.

Technical Context

The BZX55C9V1_T50R operates as a two-terminal voltage reference device relying on controlled reverse-biased avalanche breakdown. Its 9.1 V nominal zener voltage is specified at 5 mA test current (IZ), with 10 Ω dynamic impedance (ZZ) measured under those conditions.

Thermal performance is defined by a 4.0 mW/°C derating above 75°C lead temperature, and it supports operation across -65°C to +200°C junction and storage temperature range. Reverse leakage remains ≤0.1 μA at 7 V (VR), confirming stable regulation near knee voltage.

Key Specifications

Pinout & Package

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

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1N4739A and BZX55C9V1 (ON Semi), the BZX55C9V1_T50R offers identical regulation performance in the compact DO-35 form factor, making it optimal for space-limited designs where 500 mW is sufficient and second-source assurance is required.

Availability

BZX55C9V1_T50R is available at Aetrix Electronics and suitable for voltage reference, overvoltage protection, brown-out detection, and signal level translation requiring stable component supply and long-term obsolescence management.

Supply support for BZX55C9V1_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, analog, and discrete devices before its acquisition by ON Semiconductor in 2016.

The BZX55 series belongs to Fairchild's general-purpose Zener diode product line, designed for cost-effective, reliable voltage regulation and transient suppression in consumer, industrial, and computing applications.

FAQ

What is the nominal zener voltage and tolerance of the BZX55C9V1_T50R?

The BZX55C9V1_T50R has a nominal zener voltage of 9.1 V with a tolerance of ±5%, meaning its actual breakdown voltage falls between 8.5 V and 9.6 V when measured at 5 mA test current and 25°C. This tolerance band is confirmed in the Fairchild BZX55C2V4–BZX55C56 datasheet Rev. D1 and defines the device's precision as a voltage reference. The BZX55C9V1_T50R maintains this specification across its qualified operating temperature range.

What package type and marking does the BZX55C9V1_T50R use?

The BZX55C9V1_T50R uses the DO-35 glass axial package with cathode identified by a color band. Per Fairchild top-marking conventions, the second line reads "5C" and the third line reads "9V1", directly indicating its BZX55C family and 9.1 V rating. This marking aligns with JEDEC standards and enables visual identification on PCBs and reels. The BZX55C9V1_T50R's DO-35 footprint is compatible with standard axial through-hole assembly processes.

What is the maximum power dissipation and thermal derating for the BZX55C9V1_T50R?

The BZX55C9V1_T50R is rated for 500 mW power dissipation at a lead temperature (TL) of 75°C or below. Above 75°C, it derates linearly at 4.0 mW/°C - for example, at 100°C TL, maximum allowable power drops to 400 mW. This derating curve is defined in the Absolute Maximum Ratings table of the Fairchild datasheet and must be applied in thermal design. The BZX55C9V1_T50R's thermal limits ensure reliability in enclosed or high-ambient environments.

How does the dynamic impedance of the BZX55C9V1_T50R affect regulation performance?

The BZX55C9V1_T50R exhibits 10 Ω dynamic impedance (ZZ) at its 5 mA test current, meaning a ±1 mA change in zener current produces approximately ±10 mV change in output voltage. This low ZZ value ensures tight regulation under small-signal load variations typical in reference and feedback networks. The BZX55C9V1_T50R's impedance remains stable across its operating current range, supporting consistent performance in analog circuits.

Is the BZX55C9V1_T50R suitable for overvoltage protection applications?

Yes, the BZX55C9V1_T50R is commonly used for low-energy overvoltage clamping, such as protecting 9 V logic lines or sensor inputs from ESD or inductive transients. With 0.1 μA reverse leakage at 7 V and sharp 9.1 V breakdown, it remains inactive below threshold while responding rapidly above it. Its 500 mW rating supports brief surge absorption, though sustained overvoltage requires additional limiting resistance. The BZX55C9V1_T50R's DO-35 package allows easy integration into compact protection networks.