onsemi BZX84C4V7LT1

Overview

BZX84C4V7LT1 from onsemi is a 4.7 V ±5% Zener diode in SOT-23 package, rated for 225 mW power dissipation at 25°C, with 80 Ω dynamic impedance at 5 mA test current and 2 µA reverse leakage at 3.2 V, used for voltage regulation and reference in space-constrained portable electronics.

For engineers reviewing the BZX84C4V7LT1 datasheet, pinout, applications, or equivalent options, this page delivers verified electrical parameters, thermal derating behavior, SOT-23 terminal mapping, ESD robustness (Class 3, >16 kV HBM), and direct alternative options for low-voltage precision clamping.

Technical Context

This device operates as a two-terminal voltage reference by exploiting controlled reverse breakdown in silicon PN junctions. Its nominal 4.7 V Zener voltage is specified at 5 mA test current (IZT), with temperature coefficient of −3.5 mV/°C and capacitance of 260 pF at 0 V bias and 1 MHz.

The SOT-23 package features Pin 1 (Anode), Pin 2 (No Connection), and Pin 3 (Cathode), enabling unidirectional clamping with cathode polarity band marking. Thermal resistance is 556 °C/W on FR-5 board, requiring derating above 25°C at 1.8 mW/°C.

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 cathode indicated by polarity band.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX84C4V7LT1, BZX84C4V7LT3 offers no electrical difference but improves manufacturing throughput via larger reel size, while BZX84B4V7LT1 trades broader tolerance for enhanced voltage accuracy-critical in metrology-grade references but unnecessary for general-purpose clamping.

Availability

BZX84C4V7LT1 is available at Aetrix Electronics and suitable for cellular phone power management, handheld portable voltage clamping, and high-density PC board reference design requiring stable component supply and RoHS-compliant sourcing.

Supply support for BZX84C4V7LT1 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 edge applications.

The BZX84CxxxLT1 series belongs to onsemi's Zener voltage regulator product line, engineered specifically for compact, low-power voltage reference and overvoltage protection in portable and space-constrained electronic systems.

FAQ

What is the Zener voltage tolerance of BZX84C4V7LT1?

The BZX84C4V7LT1 has a nominal Zener voltage of 4.7 V with a tolerance of ±5%, meaning its actual breakdown voltage falls between 4.4 V and 5.0 V when tested at 5 mA (IZT). This tolerance is defined per the "C" series designation in the BZX84 family and is confirmed in the Electrical Characteristics table on page 3 of the official datasheet. The BZX84C4V7LT1 is not a tight-tolerance part-those are designated with "B" (e.g., BZX84B4V7LT1, ±2%).

Does BZX84C4V7LT1 have a connection on Pin 2?

No, Pin 2 of the BZX84C4V7LT1 is internally unconnected (NC). As documented in the Mechanical Characteristics and Package Dimensions sections, Pin 1 is the Anode, Pin 2 is No Connection, and Pin 3 is the Cathode. PCB layout must leave Pin 2 floating-no trace, pad, or thermal relief should tie it to any net, as doing so may compromise thermal performance or introduce unintended coupling paths.

What is the maximum power dissipation of BZX84C4V7LT1 at 70°C ambient?

At 70°C ambient, the BZX84C4V7LT1's maximum power dissipation is 144 mW. This is calculated using the derating factor of 1.8 mW/°C above 25°C: 225 mW − (70 − 25) × 1.8 mW = 225 − 81 = 144 mW. This value assumes mounting on FR-5 board per Note 1 in the Maximum Ratings table and is critical for thermal design validation in enclosed or high-temperature environments.

Is BZX84C4V7LT1 suitable for ESD protection in USB data lines?

No, the BZX84C4V7LT1 is not optimized for high-speed data line ESD protection. While it has Class 3 HBM ESD rating (>16 kV), its 260 pF capacitance at 0 V bias is too high for USB 2.0 (max ~5 pF recommended) and will distort signal integrity. It is intended for low-frequency voltage regulation and clamping-not signal-line transient suppression. For USB data lines, purpose-built low-capacitance TVS diodes such as NUP4105MR6T1G are appropriate alternatives.

Can BZX84C4V7LT1 be used as a replacement for BZX84C5V1LT1 in a 5 V regulator circuit?

No, BZX84C4V7LT1 should not directly replace BZX84C5V1LT1 in a 5 V regulator circuit because their Zener voltages differ significantly: BZX84C4V7LT1 regulates at 4.4–5.0 V, while BZX84C5V1LT1 regulates at 4.8–5.4 V. Using BZX84C4V7LT1 would lower the regulated output by up to 0.4 V, potentially causing undervoltage faults in 5 V logic. If substitution is unavoidable, verify downstream IC minimum supply requirements and recalculate series resistor values to maintain target current.