onsemi BZX84C12LT1

Overview

BZX84C12LT1 from onsemi is a 12 V, ±5% tolerance Zener diode in SOT-23 package, rated for 225 mW power dissipation on FR-5 board at 25°C, with 25 Ω dynamic impedance at 5 mA test current and 0.1 µA reverse leakage at 9.4 V. It serves as a precision voltage reference or overvoltage clamp in portable power rails.

For engineers reviewing the BZX84C12LT1 datasheet, pinout, applications, or equivalent options, key selection criteria include nominal Zener voltage (12 V), tolerance (±5%), thermal resistance (556 °C/W), junction temperature range (−65 to +150°C), and ESD rating (>16 kV HBM).

Technical Context

This device operates in reverse breakdown mode to maintain stable voltage across its cathode-anode terminals under varying load or input conditions. Its Zener voltage exhibits a +6.0 mV/°C temperature coefficient near 12 V, enabling predictable drift compensation in temperature-sensitive circuits.

The SOT-23 package features a no-connect terminal (Pin 2), allowing mechanical stability without electrical function. The device delivers 12.0 V regulation at 5 mA test current (IZT), with 150 Ω maximum impedance at 20 mA and 10 pF capacitance at 0 V bias and 1 MHz.

Key Specifications

Pinout & Package

SOT-23 plastic surface-mount package (Case 318, Style 8), void-free thermosetting body with corrosion-resistant finish, UL 94 V-0 flammability rating, and 260°C soldering tolerance for 10 seconds.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX84C12LT1, MMBZ5242BS-7-F offers smaller size but reduced power margin and thermal performance, while BZX84C12LT3G provides identical regulation behavior with Pb-free assurance and larger reel quantity-ideal for volume manufacturing without design change.

Availability

BZX84C12LT1 is available at Aetrix Electronics and suitable for smartphone power management, USB-C port protection, and industrial sensor signal conditioning requiring stable component supply, consistent parametric performance, and long-term lifecycle continuity.

Supply support for BZX84C12LT1 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 (formerly ON Semiconductor) is a global semiconductor supplier delivering energy-efficient silicon solutions for automotive, industrial, cloud, medical, and IoT applications.

The BZX84CxxxLT1 series is part of onsemi's general-purpose Zener diode portfolio, designed specifically for compact, low-power voltage regulation and transient suppression in space-constrained portable and high-density PCB environments.

FAQ

What is the Zener voltage tolerance of BZX84C12LT1?

The BZX84C12LT1 has a nominal Zener voltage of 12.0 V with a tolerance of ±5%, meaning its actual breakdown voltage falls between 11.4 V and 12.7 V when tested at 5 mA (IZT). This tolerance is specified per the standard C-series grading and confirmed in the Electrical Characteristics table on page 3 of the official datasheet.

Does BZX84C12LT1 have a built-in capacitor or ESD protection?

The BZX84C12LT1 includes inherent ESD protection rated at Class 3 (>16 kV) per Human Body Model, verified per JEDEC JS-001. It also exhibits 130 pF junction capacitance at 0 V bias and 1 MHz, which is intrinsic to its PN junction-not an added capacitor-but usable for basic RF filtering in low-speed interfaces.

Can BZX84C12LT1 be used in place of BZX84C12LT3G?

Yes, BZX84C12LT1 and BZX84C12LT3G share identical electrical specifications, thermal characteristics, and pinout. The only differences are packaging (3,000 vs. 10,000 pieces per reel) and RoHS compliance (BZX84C12LT3G is Pb-free). No PCB or schematic changes are needed for substitution in existing designs.

What is the maximum operating temperature for BZX84C12LT1?

The BZX84C12LT1 supports a junction and storage temperature range of −65°C to +150°C. Its maximum allowable junction temperature is +150°C, and it achieves this with a thermal resistance of 556 °C/W on FR-5 board-meaning ambient temperature must stay below ~105°C at full 225 mW dissipation to avoid exceeding TJ(max).

Is Pin 2 of BZX84C12LT1 electrically functional?

No, Pin 2 of BZX84C12LT1 is a no-connect terminal-mechanically present for package stability but electrically isolated. The datasheet explicitly states "2. No Connection" in both the marking diagram and package dimensions section. It must remain unconnected in PCB layout and schematic symbol.