Littelfuse LA70QS35-4 - LA70 VERY FAST-ACTI SEMICOND FUSE QS35-4. 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

LA70QS35-4

Alternate Item Number: LA70QS354

UPC: 079458152630

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Overview

The Littelfuse LA70QS35-4 is a cutting-edge, very fast-acting semiconductor fuse engineered to deliver superior protection for modern solid-state power electronic equipment. Designed by Littelfuse, a globally recognized leader in circuit protection, this fuse (SKU: LA70QS35-4) addresses the evolving performance demands of today's advanced industrial systems. Its primary function is to safeguard sensitive semiconductor devices from damaging overcurrents and short circuits, ensuring operational integrity and extending equipment lifespan. The LA70QS series, including the LA70QS35-4, distinguishes itself with several key performance enhancements. It features a significantly lower I²t (ampere squared second) rating, which is critical for minimizing the energy let-through during fault conditions. This reduced I²t directly translates to improved protection for dynamic solid-state components, preventing catastrophic failures and costly downtime. Furthermore, the superior cycling ability of this fuse makes it an ideal choice for applications subjected to frequent power fluctuations or high switching frequencies, such as those found in motor drives and power conversion systems. This enhanced durability ensures long, reliable service life even under demanding operational cycles. Another significant benefit of the Littelfuse LA70QS35-4 is its lower watts loss. This characteristic contributes to cooler operation within the protected equipment, reducing thermal stress on components and potentially allowing for more compact equipment designs due to less need for extensive heat dissipation. The robust 700 Volt AC/DC rating offers exceptional design versatility, enabling its use across a wide spectrum of applications operating at or below this voltage threshold. This broad applicability makes it a go-to solution for engineers designing systems that require reliable and efficient overcurrent protection. Key features and benefits of the Littelfuse LA70QS35-4 include: * **Very Low I²t:** Provides enhanced protection for sensitive semiconductor equipment by limiting let-through energy during fault events. * **Superior Cycling Ability:** Ensures long, reliable operational life in applications with high switching frequencies or frequent load changes. * **Lower Watts Loss:** Contributes to cooler equipment operation, reducing thermal stress and potentially enabling equipment downsizing. * **700 Volt AC/DC Rating:** Offers greater design flexibility and compatibility with a wide range of solid-state power systems. * **Compact Size:** Facilitates equipment miniaturization and space savings in densely packed control panels and enclosures. The applications for the LA70QS35-4 are extensive within the industrial sector. It is specifically designed for the protection of 700 volt or less solid-state equipment, including but not limited to: * **Motor Drives (Variable Frequency Drives - VFDs):** Protecting the power semiconductor modules within VFDs from overcurrents and short circuits, ensuring smooth motor control. * **Uninterruptible Power Supplies (UPS):** Safeguarding the critical power electronics in UPS systems that provide continuous power during outages. * **Inverters and Converters:** Protecting the semiconductor components in AC/DC and DC/AC power conversion circuits used in renewable energy, industrial automation, and power distribution. * **DC Power Supplies:** Ensuring the reliability of high-power DC power supplies used in various industrial processes. * **Industrial Automation Equipment:** Protecting a wide array of control systems and power modules within automated manufacturing environments. When selecting semiconductor fuses, engineers prioritize performance characteristics like I²t, breaking capacity, and voltage rating, alongside physical dimensions and environmental resilience. Littelfuse's reputation for quality and innovation in circuit protection makes the LA70QS35-4 a trusted component for critical applications where reliability is paramount. Its advanced design ensures that equipment operates efficiently and safely, minimizing the risk of damage and maximizing uptime. The UNSPSC code for this product is 39121628.
  • Very low I²t for improved protection of sensitive semiconductor equipment.
  • Superior cycling ability for long, reliable life in high-cycling applications.
  • Lower watts loss for cooler operation and potential equipment downsizing.
  • 700 Volt AC/DC rating provides greater design versatility.
  • Compact sizes enable equipment miniaturization and space savings.

Specifications

Application
Protection of Semiconductors
Brand Name
Littelfuse
Series
LA70QS
Special Features
Very-Fast Acting
Standard
UL Recognized
Sub Brand
LA Series
Type
Semiconductor Fuse
Voltage Rating
700 V AC/DC
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Fuse Block 600VAC 600VDC Class CC 30A 1/4in Quick Connect / Solder 90 angle screw Knob Panel Mount
Fuse Holder Modulostar® Size 10x38 IEC 690VAC 690VDC 3-Pole IP20

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Fuse Block 1500VAC 1500VDC 400A 1-Pole Stud M8

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9F61 Size B Clips 1.6in

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9F61 Size B Clips 1.6in
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.

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.