Vishay General Semiconductor - Diodes Division BZG04-20TR

Overview

BZG04-20TR from Vishay Semiconductors is a glass-passivated, surface-mount Zener diode designed for transient voltage suppression in power rails and signal lines. It features a 20 V standoff voltage, 33.8 V clamping voltage at 8.9 A peak pulse current, 300 W non-repetitive surge power rating, and DO-214AC (SMC) package - used in DC power supply overvoltage protection circuits.

For engineers reviewing the BZG04-20TR datasheet, BZG04-20TR pinout, BZG04-20TR application, or BZG04-20TR equivalent, key selection criteria include clamping voltage vs. surge current, thermal resistance to ambient (125 K/W on epoxy-glass hard tissue), junction temperature limit (150 °C), and RoHS-compliant lead-free construction.

Technical Context

The BZG04-20TR operates as a unidirectional voltage-clamping device with fast response time (≤1 ps), leveraging a glass-passivated PN junction for high reliability under repetitive transients. Its 20 V nominal standoff voltage is defined at 5 µA reverse leakage, with breakdown occurring at 22.8 V (min) under 25 mA test current.

Thermal design relies on low junction-to-lead resistance (25 K/W) and configurable junction-to-ambient performance (100–150 K/W) depending on PCB mounting - critical for sustaining 300 W surge pulses in 10/1000 µs waveform without thermal runaway.

Key Specifications

Pinout & Package

Package: DO-214AC (SMC), molded plastic case with cathode band marking; dimensions per Vishay Doc. 85594 Rev. 2.2.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZG04-20TR, SMBJ20A and P6SMB20A offer higher surge power (600 W vs. 300 W) but require DO-214AA footprint changes and provide slightly lower clamping voltage - trade-offs that impact PCB redesign effort and thermal management strategy.

Availability

BZG04-20TR is available at Aetrix Electronics and suitable for industrial power supply protection, automotive body control modules, telecom line interface circuits, and renewable energy inverter DC links requiring stable component supply and traceable RoHS-compliant sourcing.

Supply support for BZG04-20TR 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

Vishay Semiconductors is a global manufacturer specializing in discrete semiconductors and passive components, with emphasis on reliability-critical applications in automotive, industrial, and computing markets.

The BZG04-Series is engineered for high-energy transient suppression in harsh environments, targeting applications where glass passivation, precise Zener voltage tolerance, and repeatable surge performance are mandatory.

FAQ

What is the maximum clamping voltage of the BZG04-20TR under standard surge conditions?

The BZG04-20TR has a maximum clamping voltage of 33.8 V when subjected to an 8.9 A peak pulse current with a 10/1000 µs waveform, as specified in Vishay Document 85594 Rev. 2.2. This value ensures protected circuits remain within safe operating limits during transient events. The BZG04-20TR achieves this clamping performance while maintaining thermal stability up to 150 °C junction temperature.

Is the BZG04-20TR compatible with lead-free reflow soldering processes?

Yes, the BZG04-20TR is a lead-free component compliant with RoHS Directive 2002/95/EC and qualified for standard lead-free reflow profiles, including JEDEC J-STD-020 moisture sensitivity level (MSL) 1. Its glass-passivated junction and DO-214AC package ensure robustness through multiple thermal cycles. The BZG04-20TR must be stored and handled per Vishay's MSL guidelines to prevent popcorning during reflow.

How does the thermal resistance of the BZG04-20TR vary with PCB mounting configuration?

The BZG04-20TR exhibits RthJA = 125 K/W when mounted on epoxy-glass hard tissue (Fig. 1b), 150 K/W on standard FR-4, and 100 K/W on Al₂O₃ ceramic substrate - per Vishay Doc. 85594. These values directly affect maximum allowable surge repetition rate and steady-state power derating. The BZG04-20TR's junction-to-lead resistance remains fixed at 25 K/W regardless of layout.

Can the BZG04-20TR be used for bidirectional transient suppression?

No, the BZG04-20TR is a unidirectional Zener diode intended for single-polarity clamping. It conducts only in reverse breakdown (cathode positive relative to anode) and forward conduction (anode positive). For bidirectional protection, two BZG04-20TR devices must be connected in series opposition, or a dedicated bidirectional TVS like SMAJ20A should be selected. The BZG04-20TR datasheet does not specify symmetrical breakdown behavior.

What is the typical junction capacitance of the BZG04-20TR at zero bias?

The typical junction capacitance of the BZG04-20TR is 570 pF measured at VR = 0 V and f = 1 MHz, as listed in the Electrical Characteristics table of Vishay Document 85594. This capacitance impacts high-frequency signal integrity in data line applications and must be accounted for in filter design. The BZG04-20TR's capacitance decreases significantly above 5 V reverse bias, supporting its use in moderate-speed interfaces.