Avalanche Diodes – Breakdown, Transient Voltage Suppression, and High-Voltage Types

Avalanche diodes harness controlled reverse-bias breakdown to deliver critical circuit protection and voltage regulation across the electronics industry. Unlike standard rectifier diodes that fail destructively when their breakdown voltage is exceeded, avalanche diodes are engineered to conduct reliably in reverse breakdown, dissipating significant pulse energy without damage. This capability makes them the foundation of transient voltage suppression (TVS), Zener voltage regulation, and high-voltage clamping circuits that protect sensitive semiconductors from electrostatic discharge (ESD), inductive switching transients, and lightning-induced surges. ADD Components supplies avalanche diodes from Vishay, Littelfuse, ON Semiconductor, STMicroelectronics, Bourns, and Diodes Incorporated, supporting design engineers and procurement teams with reliable overvoltage protection solutions.

Sub-Types and Categories

Avalanche Breakdown Fundamentals

Avalanche breakdown occurs when a reverse-biased PN junction experiences a sufficiently high electric field that free carriers accelerate to energies capable of ionising lattice atoms upon collision. Each ionisation generates an additional electron-hole pair, which in turn accelerates and creates further pairs in a self-sustaining cascade. The voltage at which this multiplication becomes self-sustaining is the breakdown voltage (V_BR), determined primarily by doping concentration in the lightly doped side of the junction. Silicon avalanche diodes exhibit positive temperature coefficients above approximately 5.6 V, while lower-voltage Zener breakdown devices show negative coefficients — a critical distinction for precision voltage reference design where temperature-compensated reference diodes combine opposing coefficients to achieve near-zero drift. Avalanche-rated rectifiers in the 1N53xx and 1N56xx series from ON Semiconductor and STMicroelectronics provide guaranteed avalanche energy ratings for power supply and motor drive applications where inductive energy must be safely dissipated during switching events.

Transient Voltage Suppression (TVS) Diodes

TVS diodes are the primary defence against voltage transients in electronic systems, responding to overvoltage events in picoseconds — far faster than gas discharge tubes or metal-oxide varistors. A TVS diode is a large-junction avalanche diode optimised for pulse power handling, specified by its standoff voltage (V_RWM), breakdown voltage (V_BR), and clamping voltage (V_C at a specified peak pulse current). The P6KE series from Littelfuse and STMicroelectronics provides 600 W peak pulse power in DO-15 axial packages, with standoff voltages from 6.8 V to over 440 V. The SMBJ series from Bourns, Littelfuse, and Diodes Incorporated offers the same rating in compact SMB surface-mount packages. For higher-power requirements, the 1.5KE series delivers 1500 W in DO-201 packages, while SMCJ variants offer 1500 W in SMC footprints. Bidirectional TVS diodes protect AC and differential signal lines; unidirectional types suit DC rail clamping.

High-Voltage Avalanche and Zener Diodes

Zener diodes utilising avalanche multiplication in the 5.6 V to 200 V range serve dual roles as voltage references and shunt regulators. The 1N5339B (5.6 V, 5 W) from ON Semiconductor and STMicroelectronics exemplifies the popular 5 W Zener family, offering ±5% tolerance in an axial DO-15 package. Diodes Incorporated's BZX84 and BZT52 series provide precision Zener voltages in miniature SOT-23 and SOD-123 SMD packages for compact designs. For applications demanding high-voltage avalanche capability in rectification, avalanche-rated fast recovery diodes from Vishay and ON Semiconductor provide documented reverse avalanche energy ratings for switch-mode power supplies and inverter circuits, giving designers confidence in ruggedness during abnormal operating conditions.

Key Selection Parameters

• Standoff voltage (V_RWM) — Maximum DC operating voltage where leakage current remains below specified limits; must exceed the normal rail voltage of the protected circuit.

• Breakdown voltage (V_BR) — The voltage at which the device enters avalanche conduction at a specified test current; defines the onset of protection.

• Clamping voltage (V_C) — The voltage across the device during a high-current pulse event; must remain below the maximum voltage rating of the protected ICs and passives.

• Peak pulse power (P_PP) — Maximum instantaneous power the device can survive for a defined pulse waveform (typically 10/1000 μs); determines surge-handling capability.

• Peak pulse current (I_PP) — Maximum current during the pulse event; higher I_PP ratings suit lower-impedance circuits and higher energy transients.

• Zener impedance (Z_ZT) — Dynamic resistance at the test current; lower impedance provides better regulation and sharper breakdown knee characteristics.

• Temperature coefficient — Positive above ~5.6 V for avalanche diodes, negative below; critical for precision reference applications requiring compensation.

Representative Parts We Source

Send Us Your Avalanche Diode Requirements

ADD Components provides comprehensive TVS and Zener diode procurement support across the Littelfuse, Bourns, STMicroelectronics, ON Semiconductor, Diodes Incorporated, and Vishay product lines. From single-reel prototype orders of SMBJ-series TVS diodes to full production volumes of 1.5KE high-power suppressors, we ensure genuine components, competitive pricing, and reliable lead-time management throughout Asia.

Submit your bill of materials to Info@addcomponents.hk and receive a same-day quotation. For urgent protection diode requirements, contact our Hong Kong team at +852 5334 3091 or WhatsApp +852 5334 3091.

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