AK1-A Axial Leaded TVS Diodes

Introduction

Littelfuse AK1-A is a family of bidirectional, axial-leaded transient-voltage-suppression (TVS) diodes intended for high-surge protection on AC and DC lines. Built with glass-passivated junction technology, the series addresses designs exposed to severe surge-test conditions while covering reverse standoff voltages from 430 V to 860 V.

The family is notable for combining a 1 kA current rating with bidirectional operation, allowing protection of lines where either voltage polarity may occur.

What it does

AK1-A devices suppress transient overvoltage events by clamping the line once their breakdown threshold is exceeded. The series has a maximum breakdown-voltage range of 490 V to 980 V and specifies up to 10 µA reverse leakage current at normal standoff conditions.

According to the supplied series information, the diodes offer fast response, low clamping voltage, sharp breakdown voltage, and low slope resistance. Their bidirectional polarity makes them suitable for AC lines as well as DC connections that may experience positive and negative transient events.

For higher-surge-current protection arrangements, devices can be connected in series and/or parallel. The series also specifies ESD protection to IEC 61000-4-2 at 15 kV air discharge and 8 kV contact discharge.

Applications

• AC line transient protection
• DC line surge protection
• Equipment intended for severe surge-test environments
• Bidirectional protection of high-voltage signal or power connections
• Higher-current protection networks using series and/or parallel TVS arrangements
• ESD-exposed line interfaces within the stated voltage range

Design considerations

The AK1-A series uses an axial-leaded package, which may suit through-hole assemblies and layouts requiring leaded surge-protection components. The devices are capable of both reflow and wave soldering.

Select the specific device according to the protected line’s required reverse standoff voltage, with available values spanning 430 V to 860 V. Designers should also account for the corresponding breakdown-voltage range, the 1 kA current rating, and the stated operating junction temperature range of −55 °C to +125 °C. Storage temperature is specified from −55 °C to +150 °C.

For systems requiring compliance-oriented material selection, the series is RoHS compliant, lead-free, and halogen-free. It also carries UL recognition as a UL 497B isolated loop circuit protector.

Availability and further information

The source/distributor and datasheet links on this page provide further information on the Littelfuse AK1-A series, including individual device options and detailed electrical characteristics.