onsemi BZX84C20LT1

Overview

BZX84C20LT1 from onsemi is a 20 V, ±5% tolerance Zener diode in SOT-23 package, rated for 225 mW power dissipation at 25°C on FR-5 board, with 55 Ω dynamic impedance at 5 mA test current and 14 mV/°C temperature coefficient - used for voltage reference and overvoltage protection in portable power rails.

For engineers reviewing the BZX84C20LT1 datasheet, pinout, applications, or equivalent options, key selection criteria include nominal Zener voltage (20 V), tolerance (±5%), power rating (225 mW), dynamic impedance (55 Ω @ 5 mA), and thermal coefficient (14 mV/°C) in compact SOT-23 surface-mount form.

Technical Context

This device operates as a two-terminal voltage reference diode, conducting in reverse breakdown at precisely controlled 20 V nominal Zener voltage with 18.8–21.2 V min/max range. It exhibits 55 Ω dynamic impedance at I_ZT = 5 mA and 225 Ω at I_ZT = 1 mA, enabling stable regulation under varying load conditions.

Its thermal coefficient of +14 mV/°C indicates positive drift above 20 V with rising junction temperature, and it maintains ≤0.05 µA reverse leakage at VR = 14 V - critical for low-power biasing and precision reference stability in battery-powered systems.

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 max soldering temperature for 10 seconds.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX84C20LT1, MMBZ5255BLT1 offers higher power and lower impedance but demands greater drive current, while BZX84C20LT3G provides identical performance in Pb-free packaging - making the latter ideal for compliance-driven volume manufacturing without redesign.

Availability

BZX84C20LT1 is available at Aetrix Electronics and suitable for portable electronics, sensor biasing, and USB interface protection requiring stable component supply with consistent parametric performance across production lots.

Supply support for BZX84C20LT1 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, sensing, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The BZX84C20LT1 belongs to the BZX84CxxxLT1 series of standard-tolerance Zener diodes designed for compact, cost-effective voltage regulation and transient suppression in high-density portable and embedded systems.

FAQ

What is the Zener voltage tolerance of BZX84C20LT1?

The BZX84C20LT1 has a ±5% Zener voltage tolerance, meaning its nominal 20 V breakdown occurs between 18.8 V and 21.2 V at 5 mA test current (IZT). This tolerance is specified per the BZX84CxxxLT1 series standard grade, distinct from tighter-tolerance BZX84B variants. The BZX84C20LT1 datasheet confirms this range in the Electrical Characteristics table on page 3.

Can BZX84C20LT1 be used in place of BZX84C18LT1 or BZX84C22LT1?

No - BZX84C20LT1 is not a direct substitute for BZX84C18LT1 (18 V) or BZX84C22LT1 (22 V), as each part has distinct Zener voltage specifications and non-interchangeable breakdown thresholds. While all share the same SOT-23 package and 225 mW rating, their voltage bands differ by ≥2 V, making them functionally incompatible in circuits requiring precise clamping or reference levels. Always verify target voltage match before substitution.

What is the maximum reverse leakage current for BZX84C20LT1 at 14 V?

The maximum reverse leakage current for BZX84C20LT1 at VR = 14 V is 0.05 µA, as specified in the Electrical Characteristics table on page 3 of the datasheet. This value applies at TA = 25°C and reflects the device's ability to maintain high-impedance blocking behavior below its Zener knee, critical for low-power bias networks and battery-sensitive applications.

Does BZX84C20LT1 have a built-in capacitor or ESD protection?

The BZX84C20LT1 does not integrate a discrete capacitor, but its junction capacitance is 85 pF at 0 V and 1 MHz - an inherent parasitic parameter, not a designed feature. It does include Class 3 ESD protection (>16 kV HBM) per human body model, verified per JEDEC JS-001, eliminating need for external ESD components in most portable designs. This ESD rating is documented in the Specification Features section of the datasheet.

Is BZX84C20LT1 compatible with lead-free reflow soldering processes?

Yes - BZX84C20LT1 supports lead-free reflow soldering with a maximum case temperature of 260°C for 10 seconds, as stated in the Mechanical Characteristics section. Its thermosetting plastic package and corrosion-resistant finish are qualified for standard Pb-free profiles (e.g., IPC/JEDEC J-STD-020). For optimal reliability, follow onsemi's Soldering and Mounting Techniques Reference Manual (SOLDERRM/D).