Littelfuse LA70QS600-4K - VERY FAST-ACTI SEMICOND FUSE QS600-4K. Littelfuse LA70QS semiconductor fuses were developed to provide improved performance required by today’s new equipment. The LA70QS features lower I2t, improved cycling, and lower watts loss. It is the best choice for the protection of dynamic solid-state equipment. Features: Very low I2t improved protection of equipment. Superior cycling ability for long, reliable life on high cycling loading. Lower watts loss for cooler operation. 700 Volt AC/DC rating provides greater design versatility. Compact sizes allow downsizing of equipment. Applications: Protection of 700 volt or less solid state equipment such as motor drives, UPS, inverters, etc.
Littelfuse

LA70QS600-4K

Alternate Item Number: LA70QS6004K

UPC: 079458153064

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Overview

The Littelfuse LA70QS600-4K is a high-performance, very fast-acting semiconductor fuse engineered to safeguard sensitive solid-state equipment operating at up to 700V AC/DC. Designed for modern industrial applications, this fuse delivers superior protection against overcurrent events while optimizing system efficiency and reliability. As part of Littelfuse’s renowned QS series, the LA70QS600-4K represents the gold standard for semiconductor fuse protection in dynamic electrical environments where rapid response and thermal stability are critical. Semiconductor fuses like the LA70QS600-4K are essential components in power electronics, providing precise fault isolation to prevent catastrophic damage to inverters, motor drives, UPS systems, and other high-value solid-state equipment. Unlike conventional fuses, semiconductor fuses are engineered with very low I²t values, enabling them to interrupt fault currents in microseconds—far faster than standard fuses. This rapid response minimizes stress on protected components, reducing the risk of thermal runaway and extending equipment lifespan. The LA70QS600-4K’s advanced design incorporates a proprietary element configuration that ensures consistent performance across repeated cycling events, making it ideal for applications with frequent load variations. Key benefits of the Littelfuse LA70QS600-4K include: - **Very low I²t rating** for superior protection of sensitive semiconductor devices during fault conditions. - **Superior cycling capability** to withstand high-frequency load changes without degradation, ensuring long-term reliability in demanding environments. - **Lower watts loss** compared to conventional fuses, reducing heat generation and improving overall system efficiency. - **700V AC/DC voltage rating** for versatile application across a wide range of industrial power systems, including both AC and DC circuits. - **Compact footprint** that enables equipment downsizing without compromising protection, allowing for more efficient panel designs. The LA70QS600-4K is particularly well-suited for protecting dynamic solid-state equipment such as: - **Motor drives and variable frequency drives (VFDs)** in industrial automation, where precise current limiting is essential to prevent IGBT or MOSFET failure during overloads or short circuits. - **Uninterruptible Power Supplies (UPS)** in data centers, healthcare facilities, and critical infrastructure, where continuous operation and rapid fault isolation are paramount. - **Solar inverters and wind power converters** in renewable energy systems, where high-voltage DC circuits require robust overcurrent protection. - **Industrial power supplies and battery management systems** in electric vehicles, energy storage, and other high-power applications. Selecting the right semiconductor fuse requires careful consideration of several factors, including voltage rating, I²t value, interrupting rating, and thermal performance. The LA70QS600-4K excels in all these areas, offering a balance of speed, durability, and efficiency that is unmatched in its class. Its 700V rating makes it compatible with both AC and DC systems, while its low watts loss reduces the need for additional cooling, simplifying system design and lowering operational costs. Littelfuse, a global leader in circuit protection solutions, has been designing and manufacturing high-quality fuses for over a century. The company’s expertise in semiconductor protection is reflected in the LA70QS600-4K, which leverages decades of research and real-world application experience. Professionals across industries trust Littelfuse for reliable, high-performance protection solutions that meet the stringent demands of modern power electronics. Whether deployed in a factory automation system, a renewable energy installation, or a critical infrastructure project, the LA70QS600-4K delivers the performance and peace of mind that engineers and maintenance teams rely on.
  • Very low I²t for superior semiconductor protection
  • Superior cycling ability for high-frequency load changes
  • Lower watts loss for improved system efficiency
  • 700V AC/DC rating for versatile applications
  • Compact design enables equipment downsizing

Specifications

Application
Protection of Semiconductors
Brand Name
Littelfuse
Series
LA70QS
Size
Compact
Special Features
Very-Fast Acting
Standard
UL Recognized
Sub Brand
LA Series
Type
Semiconductor Fuse
Voltage Rating
700 V AC/DC
Fuse Block 600VAC 600VDC Class CC 30A 1/4in Quick Connect / Solder 90 angle screw Knob Panel Mount

GPM-SRR90

Fuse Block 600VAC 600VDC Class CC 30A 1/4in Quick Connect / Solder 90 angle screw Knob Panel Mount
Fuse Holder UltraSafe™ 800VAC 1000VDC UL Fuse size 14x51 1-Pole Visual Indicator Microswitch Pressure Plate IP20

C331156

Fuse Holder UltraSafe™ 800VAC 1000VDC UL Fuse size 14x51 1-Pole Visual Indicator Microswitch Pressure Plate IP20
Fuse Block 1500VAC 1500VDC 400A 1-Pole Stud M8

1SCM8

Fuse Block 1500VAC 1500VDC 400A 1-Pole Stud M8
Fuse Holder Modulostar® Size 10x38 IEC 690VAC 690VDC 3-Pole IP20

E1062696

Fuse Holder Modulostar® Size 10x38 IEC 690VAC 690VDC 3-Pole IP20
POWR-JAW clamps improve the contact between fuse and clip. The unnecessary heat from poor contact due to the loss of spring force in the clips can cause nuisance fuse opening and premature aging of surrounding components. High temperature phenolic resin knob designed for the most severe environments 7 sizes to provide effective coverage. Simple design makes installation easy.

LCC5

POWR-JAW clamps improve the contact between fuse and clip. The unnecessary heat from poor contact due to the loss of spring force in the clips can cause nuisance fuse opening and premature aging of surrounding components. High temperature phenolic resin knob designed for the most severe environments 7 sizes to provide effective coverage. Simple design makes installation easy.
9F61 Size B Clips 1.6in

9F61BWW460

9F61 Size B Clips 1.6in

Frequently Asked Questions about Littelfuse

What certifications and standards do Littelfuse products comply with?

Littelfuse products are certified to multiple international standards, including UL (Underwriters Laboratories), CSA (Canadian Standards Association), CCC (China Compulsory Certification), and EAC (Eurasian Conformity). Customers can verify specific product certifications by consulting individual product datasheets on Littelfuse.com, which provide comprehensive details about standards compliance for each component.

What industries and applications are Littelfuse products used for?

Littelfuse products are critical for electrical protection and safety across multiple industrial sectors, including manufacturing, automation, power distribution, and electrical control systems. Their comprehensive product portfolio serves industries that require robust electrical protection, including motor and pump applications, solar installations, programmable logic controllers (PLCs), electrical switch panels, and critical infrastructure environments. Key product lines protect against overcurrent, voltage transients, ground faults, and temperature-related electrical risks, ensuring equipment safety and operational reliability.

What technical support does Littelfuse offer?

Littelfuse offers comprehensive technical support through multiple channels. Their Technical Hotline (800-TEC-FUSE) provides direct access to engineers who can help identify issues and recommend solutions. Additionally, Littelfuse offers extensive online Technical Resources at Littelfuse.com, including datasheets, product manuals, whitepapers, application guides, and online design tools. Their experienced product and application engineers also provide step-by-step support from design to installation.

What are the main product lines offered by Littelfuse?

Littelfuse offers comprehensive industrial protection and control product lines, including fuses, fuse holders, protection relays, temperature sensors, and electrical safety components. Their key product categories span surge protective devices, custom OEM products, electrical switch panels, medium voltage fuses, ground-fault protection relays, motor and pump protection devices, and temperature sensors. These products are designed to minimize electrical safety hazards, limit equipment damage, improve productivity, and safeguard personnel from electrical faults.

What are the key features of Littelfuse products?

Littelfuse products feature exceptional circuit protection technologies with key characteristics including UL/IEC safety standard compliance, low internal resistance, and advanced protective capabilities across multiple product lines. Their components provide critical protection for industrial systems, offering features like overcurrent protection, voltage transient suppression, and resettable protection devices with ultra-low resistance and compact designs. Key product lines include fuses, metal oxide varistors (MOVs), TVS diodes, PolySwitch devices, and specialized electronic protection components that enhance system reliability and safety.

What environmental ratings do Littelfuse products have?

Littelfuse products feature comprehensive environmental ratings, including NEMA Type 1, 2, 3, 3R, 4/4X, 12, and 13 certifications, as well as IP65 protection. These ratings ensure superior protection in diverse industrial environments, with an operating temperature range of -40°F to +131°F (-40°C to +55°C). Many products also include UV-stabilized materials and neoprene gaskets for enhanced durability in outdoor and challenging conditions.

What accessories are available for Littelfuse products?

Littelfuse offers several key accessories across their product lines, including fuse holders, voltage monitoring modules, and terminal connectors. Specific accessories include the LPSM003ZXID (indicating) and LPSM003Z (non-indicating) POWR-SAFE Dead Front fuse holders for Class CC and Midget-Style fuses, the VRM6048 voltage monitor accessory module, and female quick connect terminals (P1015 series) in various wire gauge sizes. These accessories are designed to enhance protection, monitoring, and connectivity for Littelfuse electrical components.

What is Littelfuse's warranty policy?

Littelfuse provides comprehensive warranty details on their official website at www.littelfuse.com/warranty. Customers should visit this page to review the specific warranty terms and conditions for their specific product lines. For direct warranty support or questions, customers can contact Littelfuse Technical Support at 1-800-TEC-FUSE or email [email protected].

What communication protocols do Littelfuse products support?

Littelfuse supports a comprehensive range of industrial communication protocols, including PROFIBUS, PROFINET, EtherNet/IP, DeviceNet, Modbus RTU, and CANopen. Our products provide flexible connectivity solutions across multiple industrial automation platforms, enabling seamless integration with various control systems and network architectures.

How are Littelfuse products typically installed?

Littelfuse products are typically installed using specialized mounting hardware like fuse holders, blocks, and panels designed for specific industrial applications. The POWR-SAFE Dead Front holders, for example, provide optimum protection for Class CC and Midget-Style fuses, supporting installations up to 600 VAC/DC. Installation often involves using precision terminals with strain relief, such as 0.25 in. female quick connect terminals, to ensure secure and safe electrical connections in industrial control systems.