Send an Inquiry

To receive a quote for your project, please fill in the following information, and we’ll get back to you promptly.

Submit Inventory List

Please fill in the following information, and we’ll get back to you promptly.

Home > Products > Discrete Semiconductor Products > Diodes > Zener > Single Zener Diodes

onsemi BZX79C30-T50A

Name: BZX79C30-T50A
Brand: onsemi
SKU: BZX79C30-T50A
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

Compare

Part No.:: BZX79C30-T50A

Manufacturer:: onsemi

Category:: Single Zener Diodes

Package:: DO-204AH, DO-35, Axial

Datasheet:: BZX79C30-T50A.pdf

Description:: DIODE ZENER 30V 500MW DO35

Quantity:: RFQ Add To RFQ list

Payment:

Shipping:

Inventory:3,810

Please send an inquiry. Send us your inquiry, and we will respond immediately.

Product details

Overview

BZX79C30-T50A from ON Semiconductor is a 30 V, 5% tolerance, 500 mW DO-35 glass-case Zener diode optimized for voltage regulation and reference applications in power supply feedback loops, overvoltage protection circuits, and precision biasing networks. It delivers stable 30 V Zener voltage at 2 mA test current, with 80 Ω dynamic impedance and ±0.05 μA leakage at 23.5 V reverse bias.

For engineers reviewing the BZX79C30-T50A datasheet, pinout, applications, or equivalent options, key selection criteria include Zener voltage tolerance (±5%), thermal coefficient (−2 mV/°C), junction capacitance (27 pF at 0 V), maximum power dissipation (500 mW), and DO-35 package compatibility with through-hole PCB assembly.

Technical Context

The BZX79C30-T50A operates as a silicon planar Zener diode with controlled avalanche breakdown at precisely 30 V nominal. Its −2 mV/°C temperature coefficient ensures predictable voltage drift across −65°C to +200°C operating range, and its 80 Ω dynamic impedance at I_Z = 2 mA supports stable regulation under moderate load variation.

Designed for DC voltage reference and clamping, it exhibits 0.05 μA maximum leakage current at 23.5 V (0.75 × V_Z) and 1.5 V forward voltage at 100 mA, enabling bidirectional signal limiting and low-power shunt regulation without external biasing.

Key Specifications

Parameter	Value and Actual Design Meaning
Zener Voltage (V_Z)	28.0–32.0 V at I_Z = 2 mA; defines regulated output voltage window for feedback or clamp circuits
Power Dissipation (P_D)	500 mW @ T_L ≤ 75°C; sets maximum continuous shunt power before thermal derating begins
Dynamic Impedance (Z_Z)	80 Ω max at I_Z = 2 mA; determines regulation stiffness and output voltage ripple sensitivity
Leakage Current (I_R)	0.05 μA max at V_R = 23.5 V; ensures minimal quiescent current in standby or high-impedance bias networks
Junction Capacitance (C_J)	27 pF at V_R = 0 V, f = 1 MHz; impacts high-frequency noise filtering and transient response in clamp applications
Temp. Coefficient (TC)	−2 mV/°C; enables predictable voltage shift in temperature-varying environments like industrial power supplies
Forward Voltage (V_F)	1.5 V max at I_F = 100 mA; supports use as bidirectional limiter or low-loss rectifier in signal paths

Pinout & Package

DO-35 glass axial package with cathode band marking; leads are tinned copper alloy, 3/8″ length specified for thermal rating compliance.

Pin/Terminal	Circuit Role	Design Meaning
Anode	Current entry terminal in forward bias; connected to lower-potential node	Enables standard diode conduction path and defines polarity for shunt regulator configuration
Cathode	Current exit terminal in forward bias; marked with color band	Identifies Zener breakdown terminal; must connect to higher-potential node for regulation/clamp operation

Key Features

Feature	Design Value
±5% Zener voltage tolerance	Ensures tight initial accuracy without post-manufacturing trimming in cost-sensitive consumer and industrial designs
−2 mV/°C temperature coefficient	Minimizes voltage drift over wide ambient ranges, critical for stable references in unregulated power rails
DO-35 glass package	Provides hermetic sealing and proven reliability for long-term operation in harsh thermal cycling environments
500 mW power rating	Supports direct shunt regulation of low-current analog stages without heatsinking or active buffering
0.05 μA max leakage at 23.5 V	Reduces standby power loss in battery-backed or energy-harvesting systems where microamp-level currents matter

Applications

Power Supply Feedback	Overvoltage Clamp
Use Scenario: Regulating output voltage in isolated flyback or buck-derived DC-DC converters using optocoupler feedback. IC Role / Device Role / Timing Role: Precision voltage reference for TL431-like error amplifier input or direct comparator threshold. Use Value: Maintains ±5% output accuracy over line/load/temperature with no external calibration required.	Use Scenario: Protecting microcontroller I/O pins or ADC inputs from ESD-induced transients or supply rail overshoot. IC Role / Device Role / Timing Role: Bidirectional voltage limiter clamping both positive and negative excursions. Use Value: Limits voltage to ≤32 V peak while drawing <0.05 μA below 23.5 V, preserving signal integrity and low-power operation.
Reference Bias Network	Current Source Stabilizer
Use Scenario: Generating stable bias voltages for op-amp input stages, sensor excitation, or DAC reference buffers. IC Role / Device Role / Timing Role: Low-drift, low-noise shunt reference replacing bulkier IC-based solutions. Use Value: Delivers 30 V reference with <80 Ω dynamic impedance, reducing sensitivity to source impedance variations.	Use Scenario: Stabilizing constant-current LED drivers or laser diode bias circuits against supply fluctuations. IC Role / Device Role / Timing Role: Shunt regulator defining current-set resistor voltage drop. Use Value: Enables accurate current setting within ±5% tolerance, independent of input voltage changes up to 32 V.

Power Supply Feedback

Overvoltage Clamp

Use Scenario: Regulating output voltage in isolated flyback or buck-derived DC-DC converters using optocoupler feedback.

IC Role / Device Role / Timing Role: Precision voltage reference for TL431-like error amplifier input or direct comparator threshold.

Use Value: Maintains ±5% output accuracy over line/load/temperature with no external calibration required.

Use Scenario: Protecting microcontroller I/O pins or ADC inputs from ESD-induced transients or supply rail overshoot.

IC Role / Device Role / Timing Role: Bidirectional voltage limiter clamping both positive and negative excursions.

Use Value: Limits voltage to ≤32 V peak while drawing <0.05 μA below 23.5 V, preserving signal integrity and low-power operation.

Reference Bias Network

Current Source Stabilizer

Use Scenario: Generating stable bias voltages for op-amp input stages, sensor excitation, or DAC reference buffers.

IC Role / Device Role / Timing Role: Low-drift, low-noise shunt reference replacing bulkier IC-based solutions.

Use Value: Delivers 30 V reference with <80 Ω dynamic impedance, reducing sensitivity to source impedance variations.

Use Scenario: Stabilizing constant-current LED drivers or laser diode bias circuits against supply fluctuations.

IC Role / Device Role / Timing Role: Shunt regulator defining current-set resistor voltage drop.

Use Value: Enables accurate current setting within ±5% tolerance, independent of input voltage changes up to 32 V.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
1N4745A	Same 30 V nominal, but ±5% tolerance and 1 W power rating in DO-41 package	Higher power handling supports >500 mW continuous dissipation; larger DO-41 footprint requires layout change	Select when thermal margin or surge energy absorption is prioritized over board space
BZX55C30	Same 30 V, ±5%, DO-35 package, but 500 mW rating and 100 Ω Z_Z at 2 mA	Slightly higher dynamic impedance reduces regulation precision; identical mounting and footprint	Choose for legacy design continuity where minor Z_Z increase is acceptable

Compared with BZX79C30-T50A, the 1N4745A offers higher power capacity but requires PCB rework, while the BZX55C30 matches the DO-35 form factor but trades 20 Ω higher impedance for equivalent voltage accuracy-making BZX79C30-T50A optimal for space-constrained, precision-shunt applications.

Availability

BZX79C30-T50A is available at Aetrix Electronics and suitable for power supply feedback, overvoltage clamp, and reference bias network applications requiring stable component supply, consistent parametric performance, and long-lifecycle availability.

Supply support for BZX79C30-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 management, analog, sensing, and connectivity solutions for automotive, industrial, and cloud infrastructure markets.

The BZX79C series is part of ON Semiconductor's legacy Zener diode portfolio designed specifically for general-purpose voltage regulation, clamping, and reference functions in cost-sensitive, high-reliability through-hole applications.

FAQ

What is the Zener voltage tolerance for BZX79C30-T50A?

The BZX79C30-T50A has a ±5% Zener voltage tolerance, meaning its nominal 30 V breakdown occurs between 28.0 V and 32.0 V at the specified test current of 2 mA. This tolerance is guaranteed per ON Semiconductor's datasheet revision 3 and applies across the full operating temperature range of −65°C to +200°C. The BZX79C30-T50A achieves this consistency via tightly controlled silicon doping and process calibration during manufacturing.

Does BZX79C30-T50A support bidirectional voltage limiting?

Yes, the BZX79C30-T50A supports bidirectional voltage limiting: in forward bias, it conducts with ≤1.5 V drop at 100 mA; in reverse bias, it regulates at ~30 V. This dual-mode behavior allows the BZX79C30-T50A to clamp both positive overvoltages (via Zener action) and negative transients (via forward conduction), making it suitable for protecting sensitive analog inputs without additional series components.

What is the maximum leakage current specification for BZX79C30-T50A?

The BZX79C30-T50A specifies a maximum leakage current of 0.05 μA at a reverse voltage of 23.5 V (75% of nominal V_Z). This ultra-low leakage is confirmed in the ON Semiconductor datasheet and ensures minimal parasitic loading in high-impedance reference or bias networks-critical for battery-powered sensors and precision instrumentation where microamp-level currents directly impact system runtime and accuracy.

Is BZX79C30-T50A compatible with lead-free soldering processes?

Yes, the BZX79C30-T50A features tinned copper alloy leads qualified for standard lead-free reflow profiles, including peak temperatures up to 260°C for 10 seconds. Its DO-35 glass package maintains mechanical and electrical integrity under JEDEC J-STD-020-compliant conditions. The BZX79C30-T50A is RoHS-compliant and rated for MSL Level 1, eliminating moisture sensitivity concerns during assembly.

How does the temperature coefficient affect BZX79C30-T50A performance in real-world circuits?

The BZX79C30-T50A has a temperature coefficient of −2 mV/°C, meaning its Zener voltage decreases by approximately 2 mV for every 1°C rise in junction temperature. In practice, this results in a total shift of ~−150 mV over a 75°C rise (e.g., from 25°C to 100°C), which is fully characterized and stable. Designers account for this in BZX79C30-T50A applications by selecting appropriate thermal margins or pairing it with complementary TC components in precision references.

BZX79C30-T50A Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: DO-204AH, DO-35, Axial

Packaging:: Cut Tape (CT)

Product Status:: Obsolete

Voltage - Zener (Nom) (Vz):: 30 V

Tolerance:: ±5%

Power - Max:: 500 mW

Impedance (Max) (Zzt):: 80 Ohms

Current - Reverse Leakage @ Vr:: 50 nA @ 21 V

Voltage - Forward (Vf) (Max) @ If:: 1.5 V @ 100 mA

Operating Temperature:: -65°C ~ 200°C

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: DO-35

BZX79C30-T50A FAQ

1.How can I place an order for BZX79C30-T50A through Aetrix?

Please submit a Request for Quotation (RFQ) for BZX79C30-T50A on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for BZX79C30-T50A reliable?

The price and inventory of BZX79C30-T50A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BZX79C30-T50A is usually 5 days.

3.What payment methods are accepted for BZX79C30-T50A?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZX79C30-T50A transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BZX79C30-T50A?

BZX79C30-T50A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BZX79C30-T50A order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for BZX79C30-T50A?

For technical support, including BZX79C30-T50A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZX79C30-T50A requirements.

6.How does Aetrix verify that BZX79C30-T50A is sourced from the original manufacturer or authorized distributors?

All BZX79C30-T50A products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that BZX79C30-T50A meets industry standards.

7.What is the process for return or replacement of BZX79C30-T50A?

All BZX79C30-T50A units undergo pre-shipment inspection (PSI). If there is an issue with BZX79C30-T50A, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The BZX79C30-T50A part is unused and in its original packaging.

Return procedure for BZX79C30-T50A:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

Tech Hub

2026-09-09 Counterfeit Electronic Components: How to Detect, Authenticate, and Test Suspect Parts

Counterfeit components can hide behind convincing markings and passing basic function tests. This engineering reference covers source traceability, external inspection, X-ray, XRF, electrical testing, …

2026-09-08 Obsolete Electronic Components: How to Source and Evaluate Replacements

A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.

2026-09-07 TTL vs CMOS Logic Levels: 74HC and 74HCT Compatibility Explained

TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.

2026-09-04 Logic Level Shifter: How to Connect 3.3V and 5V Logic Safely

A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.

2026-09-03 74HC595 vs TPIC6B595: Output Drive, Pinout, Current, and Load Selection

The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…

2026-09-02 74HC595 Pinout, Timing, Output Current, and Applications

The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…

2026-09-01 Latch vs Flip-Flop: Timing, Differences and Design Choices

A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…

2026-08-30 D Latch Circuit: Truth Table, Timing, ICs and Applications

A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …

2026-08-28 SR Latch Explained: NOR and NAND Circuits, Truth Tables, and Applications

An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…

2026-08-27 Latch Circuit: SR and D Latches, Truth Tables, Timing, and Applications

Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…