onsemi BZX84C27LT3G

Overview

BZX84C27LT3G from onsemi is a 27 V ±5% tolerance Zener diode in SOT-23 package, rated for 250 mW power dissipation at 25°C, with 80 Ω dynamic impedance at 5 mA test current and 0.05 μA reverse leakage at 20.3 V. It provides precision voltage regulation in space-constrained DC biasing and reference circuits.

For engineers reviewing the BZX84C27LT3G datasheet, pinout, applications, or equivalent options, key selection criteria include nominal Zener voltage (27 V), tolerance (±5%), thermal coefficient (+18.9 mV/°C), low capacitance (70 pF), and SOT-23 footprint compatibility with high-density PCB layouts.

Technical Context

This device operates as a two-terminal voltage reference diode, conducting in reverse breakdown to clamp or regulate voltage across its cathode-anode terminals. Its Zener mechanism delivers stable 27 V output under controlled current conditions (IZT = 5 mA), with temperature coefficient of +18.9 mV/°C ensuring predictable drift over −65°C to +150°C junction range.

The SOT-23 package features pin 1 (anode), pin 2 (no connection), and pin 3 (cathode), enabling unidirectional clamping in low-power analog signal conditioning and supply rail stabilization. ESD rating exceeds 16 kV (HBM Class 3) and it is Pb-free/RoHS compliant.

Key Specifications

Pinout & Package

SOT-23 (TO-236) surface-mount plastic package, 2.90 × 1.30 × 1.00 mm, void-free thermosetting case with corrosion-resistant finish; polarity indicated by cathode band; UL 94 V-0 flammability rating.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX84C27LT3G, BZX84C27LT1G offers identical performance in a smaller reel format ideal for development, while BZX84B27LT1G trades wider tolerance for improved initial accuracy-enabling higher-precision references without footprint change or thermal redesign.

Availability

BZX84C27LT3G is available at Aetrix Electronics and suitable for power supply clamping, analog reference generation, LED biasing, and signal translation requiring stable component supply and long-term manufacturing continuity.

Supply support for BZX84C27LT3G 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 specializing in energy-efficient power, analog, sensor, and logic solutions for automotive, industrial, cloud, and consumer markets.

The BZX84Cxxx series targets cost-effective, space-efficient voltage regulation in portable electronics and high-density PCBs, emphasizing manufacturability, reliability, and environmental compliance.

FAQ

What is the Zener voltage tolerance of BZX84C27LT3G?

The BZX84C27LT3G has a nominal Zener voltage of 27 V with a tolerance of ±5%, meaning its actual breakdown voltage falls between 25.1 V and 28.9 V when tested at 5 mA (IZT). This tolerance is specified per onsemi's BZX84CxxxLTxG series datasheet Rev. 23 and applies directly to the BZX84C27LT3G variant.

Can BZX84C27LT3G be used in automotive applications?

Yes - the BZX84C27LT3G is RoHS compliant and Pb-free, and belongs to the standard BZX84C series qualified for industrial temperature range (−65°C to +150°C). While not AEC-Q101 certified itself, its SZ-prefix counterpart (SZBZX84C27LT3G) is explicitly AEC-Q101 qualified and PPAP capable; BZX84C27LT3G may be used in non-safety-critical automotive subsystems where full qualification is not mandated.

What is the thermal resistance of BZX84C27LT3G on FR-5 board?

The thermal resistance from junction-to-ambient (R_JA) for BZX84C27LT3G mounted on FR-5 board is 500°C/W, with a maximum power dissipation of 250 mW at 25°C ambient. Above 25°C, power must be linearly derated by 2.0 mW/°C - a critical parameter for thermal design validation in enclosed or high-ambient environments.

Does BZX84C27LT3G have a built-in capacitor or ESD protection?

The BZX84C27LT3G integrates no additional passive components, but it features inherent ESD robustness rated at Class 3 (>16 kV) per Human Body Model. Its junction capacitance is 70 pF at 0 V bias and 1 MHz - a parasitic value arising from the PN junction, not a discrete capacitor. No external ESD diode is required for basic handling protection in typical board-level environments.

How does the temperature coefficient affect BZX84C27LT3G's regulation accuracy?

The BZX84C27LT3G exhibits a positive temperature coefficient of +18.9 mV/°C at 5 mA, meaning its Zener voltage increases by ~18.9 mV per degree Celsius rise in junction temperature. Over a 100°C operating range, this results in up to ±1.89 V drift - a key factor when designing stable references for wide-temperature applications; compensation techniques or tighter-tolerance variants like BZX84B27LT1G may be needed for <±0.5% stability.