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

onsemi BZX84C12ET1G

Name: BZX84C12ET1G
Brand: onsemi
SKU: BZX84C12ET1G
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BZX84C12ET1G

Manufacturer:: onsemi

Category:: Single Zener Diodes

Package:: TO-236-3, SC-59, SOT-23-3

Datasheet:: BZX84C12ET1G.pdf

Description:: DIODE ZENER 12V 225MW SOT23

Quantity:: RFQ Add To RFQ list

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Inventory:8,737

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Product details

Overview

BZX84C12ET1G from onsemi is a 250 mW, 12 V Zener diode in SOT-23 package, designed for precision voltage regulation and reference applications in space-constrained circuits. It delivers nominal Zener voltage of 12 V at 5 mA test current, with dynamic impedance of 25 Ω, ±10% voltage tolerance, and 0.1 µA reverse leakage at 9.5 V. It is widely deployed in power supply feedback loops, overvoltage protection, and voltage clamping in portable electronics.

For engineers reviewing the BZX84C12ET1G datasheet, pinout, applications, or equivalent options, key selection criteria include Zener voltage accuracy (11.4–12.7 V), thermal coefficient (+6.0 mV/°C), low capacitance (130 pF @ 0 V), ESD robustness (>16 kV HBM), and SOT-23 footprint compatibility for high-density PCB layouts.

Technical Context

This device operates as a two-terminal, silicon planar Zener diode optimized for stable reverse-biased breakdown regulation. Its 12 V nominal Zener voltage is specified at I_ZT = 5 mA with tight 25 Ω dynamic impedance, enabling low-noise voltage references in analog circuitry and feedback networks.

The SOT-23 package features a defined pinout (Pin 1: Anode, Pin 2: No Connection, Pin 3: Cathode) and supports automated placement. Thermal resistance is 500 °C/W on FR-5 board, and junction temperature range spans −65 °C to +150 °C - suitable for industrial and consumer environments.

Key Specifications

Parameter	Value and Actual Design Meaning
Zener Voltage (V_Z)	11.4–12.7 V at 5 mA - ensures stable regulation within ±5.3% tolerance for feedback and reference use.
Zener Impedance (Z_ZT)	25 Ω max at 5 mA - minimizes output voltage variation under load transients in regulator circuits.
Power Dissipation	250 mW on FR-5 board - defines maximum continuous DC power handling without derating.
Reverse Leakage (I_R)	0.1 µA max at 9.5 V - guarantees low quiescent current in standby or battery-powered clamp circuits.
Capacitance (C)	130 pF at 0 V, 1 MHz - impacts high-frequency noise filtering and signal integrity in RF-adjacent designs.
Temperature Coefficient	+6.0 mV/°C at 5 mA - enables predictable drift compensation in temperature-sensitive references.
ESD Rating	Class 3 (>16 kV HBM) - provides robust handling during assembly and operation in handheld devices.

Pinout & Package

SOT-23 (TO-236) surface-mount package: 2.90 mm × 1.30 mm × 1.00 mm body, 1.90 mm lead pitch, void-free thermosetting plastic case with corrosion-resistant finish. Cathode indicated by polarity band.

Pin/Terminal	Circuit Role	Design Meaning
1	Anode	Forward-biased terminal; connects to lower-potential node in Zener clamp/regulator configuration.
2	No Connection	Internally unconnected; must remain floating - no PCB trace or pad required.
3	Cathode	Breakdown terminal; connects to regulated voltage node or feedback point in switching PSUs.

Key Features

Feature	Design Value
250 mW Power Rating	Enables compact voltage regulation without heatsinking in low-power embedded systems.
Low Dynamic Impedance (25 Ω)	Reduces output voltage deviation under varying load currents in precision reference paths.
130 pF Junction Capacitance	Minimizes signal coupling and phase shift in high-speed clamping or AC-coupled bias networks.
−65 °C to +150 °C Operating Range	Supports deployment in automotive cabin modules and industrial controllers without thermal derating.
Pb-Free & RoHS Compliant	Meets global environmental compliance requirements for consumer and medical electronics manufacturing.

Applications

Switching Power Supply Feedback	Overvoltage Protection Clamp
Use Scenario: Used in optocoupler-based feedback loop of isolated DC-DC converters to regulate output voltage. IC Role / Device Role / Timing Role: Zener reference element setting error amplifier threshold; replaces bulkier TL431 in cost-sensitive designs. Use Value: Tight 12 V tolerance and 25 Ω Z_ZT ensure <±1% output regulation across line/load variations.	Use Scenario: Placed across microcontroller I/O pins or sensor inputs to limit transient overvoltage. IC Role / Device Role / Timing Role: Fast-acting shunt clamp absorbing ESD or inductive kick energy before damage occurs. Use Value: 16 kV HBM rating and 225 W peak pulse capability protect against common-mode surges in portable gear.
Portable Device Voltage Reference	LED Current Regulation Bias
Use Scenario: Provides stable 12 V reference for ADC voltage scaling in handheld test equipment. IC Role / Device Role / Timing Role: Precision voltage source for ratiometric measurement circuits requiring low drift. Use Value: +6.0 mV/°C TC allows predictable calibration offset correction over −20 °C to +70 °C operating range.	Use Scenario: Sets bias voltage for constant-current LED driver ICs in backlight or status indicator circuits. IC Role / Device Role / Timing Role: Stable Zener node defining reference voltage for current-sense amplifier thresholds. Use Value: Low 0.1 µA leakage at 9.5 V prevents unintended turn-on in low-duty-cycle LED flash applications.

Switching Power Supply Feedback

Overvoltage Protection Clamp

Use Scenario: Used in optocoupler-based feedback loop of isolated DC-DC converters to regulate output voltage.

IC Role / Device Role / Timing Role: Zener reference element setting error amplifier threshold; replaces bulkier TL431 in cost-sensitive designs.

Use Value: Tight 12 V tolerance and 25 Ω Z_ZT ensure <±1% output regulation across line/load variations.

Use Scenario: Placed across microcontroller I/O pins or sensor inputs to limit transient overvoltage.

IC Role / Device Role / Timing Role: Fast-acting shunt clamp absorbing ESD or inductive kick energy before damage occurs.

Use Value: 16 kV HBM rating and 225 W peak pulse capability protect against common-mode surges in portable gear.

Portable Device Voltage Reference

LED Current Regulation Bias

Use Scenario: Provides stable 12 V reference for ADC voltage scaling in handheld test equipment.

IC Role / Device Role / Timing Role: Precision voltage source for ratiometric measurement circuits requiring low drift.

Use Value: +6.0 mV/°C TC allows predictable calibration offset correction over −20 °C to +70 °C operating range.

Use Scenario: Sets bias voltage for constant-current LED driver ICs in backlight or status indicator circuits.

IC Role / Device Role / Timing Role: Stable Zener node defining reference voltage for current-sense amplifier thresholds.

Use Value: Low 0.1 µA leakage at 9.5 V prevents unintended turn-on in low-duty-cycle LED flash applications.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MMBZ5242BS-7-F	12 V nominal, 200 mW rating, 30 Ω Z_ZT, SOT-23 package, ±5% tolerance	Higher Z_ZT and lower power limit reduce regulation stability under dynamic loads	Acceptable for non-critical biasing where tighter voltage control is not required
BZX84-C12LT1G	Identical 12 V spec, same SOT-23 package, but rated at 300 mW on FR-5 board	Higher power margin allows extended operation at elevated ambient temperatures	Preferred when thermal headroom exceeds 250 mW requirement or derating is needed

Compared with BZX84C12ET1G, MMBZ5242BS-7-F offers lower cost but sacrifices regulation precision and surge robustness, while BZX84-C12LT1G provides higher power headroom at identical voltage performance - making it suitable for thermally demanding deployments without layout change.

Availability

BZX84C12ET1G is available at Aetrix Electronics and suitable for switching power supplies, overvoltage protection circuits, and portable device voltage references requiring stable component supply and long-term production continuity.

Supply support for BZX84C12ET1G 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

onsemi is a global semiconductor supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, and IoT applications.

The BZX84C12ET1G belongs to the BZX84CxxxET1G Zener regulator series, engineered for high-density surface-mount voltage reference and clamping in portable, battery-powered, and space-constrained electronic systems.

FAQ

What is the Zener voltage tolerance of BZX84C12ET1G?

The BZX84C12ET1G has a nominal Zener voltage of 12 V with a guaranteed range of 11.4 V to 12.7 V at 5 mA test current, corresponding to ±5.3% tolerance. This specification is verified per onsemi's Electrical Characteristics table and applies under standard test conditions (T_A = 25 °C). The BZX84C12ET1G maintains this tolerance across its full operating temperature range when used within rated power limits.

Does BZX84C12ET1G have a built-in capacitor or integrated circuitry?

No, the BZX84C12ET1G is a discrete silicon planar Zener diode with no integrated capacitors, resistors, or active circuitry. It functions solely as a two-terminal voltage-reference device relying on controlled reverse breakdown. Its 130 pF junction capacitance is an inherent parasitic parameter - not a designed-in feature - and varies with applied bias voltage as shown in Figure 5 of the datasheet.

Can BZX84C12ET1G be used in place of a 12 V linear regulator?

The BZX84C12ET1G is not a replacement for a linear regulator IC like the LM7812. It lacks current-limiting, thermal shutdown, and dropout regulation capabilities. However, the BZX84C12ET1G can serve as the voltage-setting element in simple shunt regulators or feedback references where external current limiting and thermal management are provided by discrete components.

What is the meaning of "ET1G" in BZX84C12ET1G?

In BZX84C12ET1G, "ET1G" denotes the packaging and environmental specification: "E" indicates SOT-23 package, "T1" specifies tape-and-reel shipping format (3,000 units per reel), and "G" certifies Pb-free and RoHS-compliant construction. This suffix distinguishes it from legacy leaded variants and confirms compliance with modern environmental directives applicable to the BZX84C12ET1G.

Is Pin 2 of BZX84C12ET1G electrically connected internally?

No, Pin 2 of the BZX84C12ET1G is explicitly designated as "No Connection" in the official datasheet's marking diagram and mechanical outline (Style 8). It is not bonded to any internal die structure and must remain unconnected on the PCB. Routing traces or applying solder to Pin 2 may compromise reliability or cause unintended electrical behavior in the BZX84C12ET1G.

BZX84C12ET1G Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-236-3, SC-59, SOT-23-3

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Voltage - Zener (Nom) (Vz):: 12 V

Tolerance:: ±5%

Power - Max:: 225 mW

Impedance (Max) (Zzt):: 25 Ohms

Current - Reverse Leakage @ Vr:: 100 nA @ 8 V

Voltage - Forward (Vf) (Max) @ If:: 900 mV @ 10 mA

Operating Temperature:: -65°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-23-3 (TO-236)

BZX84C12ET1G FAQ

1.How can I place an order for BZX84C12ET1G through Aetrix?

Please submit a Request for Quotation (RFQ) for BZX84C12ET1G 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 BZX84C12ET1G reliable?

The price and inventory of BZX84C12ET1G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BZX84C12ET1G is usually 5 days.

3.What payment methods are accepted for BZX84C12ET1G?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BZX84C12ET1G transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BZX84C12ET1G?

BZX84C12ET1G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BZX84C12ET1G 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 BZX84C12ET1G?

For technical support, including BZX84C12ET1G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BZX84C12ET1G requirements.

6.How does Aetrix verify that BZX84C12ET1G is sourced from the original manufacturer or authorized distributors?

All BZX84C12ET1G 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 BZX84C12ET1G meets industry standards.

7.What is the process for return or replacement of BZX84C12ET1G?

All BZX84C12ET1G units undergo pre-shipment inspection (PSI). If there is an issue with BZX84C12ET1G, 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 BZX84C12ET1G part is unused and in its original packaging.

Return procedure for BZX84C12ET1G:

1.Submit a request within 90 days.

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

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