Semiconductor Fuses

The POWR-SPEED® line of semiconductor fuses is designed for modern day sensitive power electronics devices that require superior protection against overcurrent. They offer extreme current limiting protection, balanced performance for longevity, and are available in direct bus-bar mount flush-end and blade designs to meet the needs of a global market.

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PSR Flush End Series – High-Speed Semiconductor Fuse, Square Body Datasheet Series Details Order Samples Littelfuse PSR Flush End, High-Speed Fuses Provide Superior Protection Amps (A): 40, 50, 63, 80, 100, 125, 160, 200, 250, 280, 315, 350, 400, 450, 500, 550, 630, 700, 800, 900 more Interrupting Rating: 100 kA @ 1000 Vac, 100 kA @ 1050 Vac, 100 kA @ 1100 Vac, 100 kA @ 1200 Vac, 100 kA @ 1300 Vac, 100 kA @ 900 Vac, 200 kA @ 500 Vac, 200 kA @ 550 Vac, 200 kA @ 600 Vac, 200 kA @ 650 Vac more Opening: Very Fast-Acting (FF)	PSR Bolted Blade Series – High-Speed Semiconductor Fuse, Square Body Datasheet Series Details Order Samples The PSR Bolted Blade series is a POWR-SPEED® high-speed, square body fuse specifically designed for ...More Amps (A): 40, 50, 63, 80, 100, 125, 160, 200, 250, 280, 315, 350, 400, 450, 500, 550, 630, 700, 800, 900 more Interrupting Rating: 100 kA @ 1000 Vac, 100 kA @ 1050 Vac, 100 kA @ 1100 Vac, 100 kA @ 1200 Vac, 100 kA @ 1300 Vac, 100 kA @ 900 Vac, 200 kA @ 500 Vac, 200 kA @ 550 Vac, 200 kA @ 600 Vac, 200 kA @ 650 Vac more Opening: Very Fast-Acting (FF)	PSR DIN Blade Series – High-Speed Semiconductor Fuse, Square Body Datasheet Series Details Order Samples The PSR DIN Blade series is a POWR-SPEED® high-speed, square body fuse specifically designed for the...More Amps (A): 40, 50, 63, 80, 100, 125, 160, 200, 250, 280, 315, 350, 400, 450, 500, 550, 630, 700, 800, 900 more Interrupting Rating: 100 kA @ 1000 Vac, 100 kA @ 1050 Vac, 100 kA @ 1100 Vac, 100 kA @ 1200 Vac, 100 kA @ 1300 Vac, 100 kA @ 900 Vac, 200 kA @ 500 Vac, 200 kA @ 550 Vac, 200 kA @ 600 Vac, 200 kA @ 650 Vac more Opening: Very Fast-Acting (FF)
L50QS Series – High-Speed Semiconductor Fuse, Round Body Datasheet Series Details Order Samples The L50QS series is a POWR-SPEED® next-generation, high-speed fuse used for the protection of power ...More Amps (A): 35, 40, 50, 60, 70, 80, 90, 100, 125, 150, 175, 200, 225, 250, 275, 300, 325, 350, 400, 450 more Interrupting Rating: 200 kA @ 500 Vac Opening: Very Fast-Acting (FF)	L60QS Datasheet Series Details Order Samples The Littelfuse QS series of High-speed Semiconductor Fuses is designed to safeguard power semiconduc...More Amps (A): 40 Interrupting Rating: 200 kA @ 600 Vac Nominal Melting I²T (A²sec): 277	L70QS Series – High-Speed Semiconductor Fuse, Round Body Datasheet Series Details Order Samples The L70QS series is a POWR-SPEED® next-generation, high-speed fuse used for the protection of power ...More Amps (A): 35, 40, 50, 60, 70, 80, 90, 100, 125, 150, 175, 200, 225, 250, 300, 350, 400, 450, 500, 600 more Interrupting Rating: 200 kA @ 700 Vac Opening: Very Fast-Acting (FF)
L75QS Series – High-Speed Semiconductor Fuse, Round Body Datasheet Series Details Order Samples The L75QS series is a POWR-SPEED® next-generation, high-speed fuse used for the protection of power ...More Amps (A): 35, 40, 50, 60, 70, 80, 90, 100, 125, 150, 175, 200, 225, 250, 300, 350, 400, 450, 500, 600 more Interrupting Rating: 50 kA @ 750 Vdc Opening: Very Fast-Acting (FF)	L70S Series – High-Speed Semiconductor Fuse Datasheet Series Details Order Samples Littelfuse L70S High-Speed Fuses Provide Superior Protection Amps (A): 10, 15, 20, 25, 30, 35, 40, 50, 60, 70, 80, 90, 100, 125, 150, 175, 200, 225, 250, 300 more Interrupting Rating: 20 kA @ 650 Vdc Opening: Very Fast-Acting (FF)	L50S Series – High-Speed Semiconductor Fuse Datasheet Series Details Order Samples Littelfuse L50S High-Speed Fuses Provide Superior Protection Amps (A): 10, 12, 15, 20, 25, 30, 35, 40, 50, 60, 70, 80, 90, 100, 125, 150, 175, 200, 225, 250 more Interrupting Rating: 20 kA @ 450 Vdc, 200 kA @ 500 Vac Opening: Very Fast-Acting (FF)
KLC Series – High-Speed Semiconductor Fuse Datasheet Series Details Order Samples Littelfuse KLC High-Speed Fuses Provide Superior Protection Amps (A): 1, 2, 3, 4, 5, 6, 7, 8, 10, 12, 15, 17.5, 20, 25, 30, 35, 40, 45, 50, 60 more Interrupting Rating: 200 kA @ 600 Vac Opening: Very Fast-Acting (FF)	L15S Series – High-Speed Semiconductor Fuse Datasheet Series Details Order Samples Littelfuse L15S High-Speed Fuses Provide Superior Protection Amps (A): 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 20, 25, 30, 35, 40, 45, 50, 60 more Interrupting Rating: 100 kA @ 150 Vac, 20 kA @ 100 Vdc Opening: Very Fast-Acting (FF)	L25S Series – High-Speed Semiconductor Fuse Datasheet Series Details Order Samples Littelfuse L25S High-Speed Fuses Provide Superior Protection Amps (A): 1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80 more Interrupting Rating: 20 kA @ 200 Vdc, 20 kA @ 250 Vdc Opening: Very Fast-Acting (FF)
L60S Series – High-Speed Semiconductor Fuse Datasheet Series Details Order Samples Littelfuse L60S High-Speed Fuses Provide Superior Protection Amps (A): 1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 17.5, 20, 25, 30, 35, 40, 45, 50, 60, 70 more Interrupting Rating: 200 kA @ 600 Vac Opening: Very Fast-Acting (FF)	PSX Series – High-Speed Semiconductor Fuse, Square Body Datasheet Series Details Order Samples The PSX series is a POWR-SPEED® high-speed, square body fuse specifically designed to protect batter...More Amps (A): 80, 100, 125, 160, 200, 250, 280, 315, 350, 400, 450, 500, 550, 630, 700, 800, 900, 1000, 1100, 1250 more Interrupting Rating: 250 kA @ 1500 Vdc Opening: aBat

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Applications
Fundamentals
Selection

A power semiconductor device is a high power electronic device that is used as a switch for control and conversion in electric power. The use of power semiconductor devices in modern power electronics is driven by the need for better power efficiency, with the ultimate goal of achieving as close to 100% power efficiency as possible. In addition to power efficiency, there is a need to make the device as small as possible, which is a driving factor as to why power semiconductors have replaced older electro-mechanical components.

Typical equipment using power semiconductor devices includes inverters, rectifiers, electric vehicle battery management systems, locomotive traction drives, industrial motor drives, factory automation systems, air conditioners, computers, telecom devices, battery chargers, and many more. To protect these very sensitive power semiconductor devices from an overcurrent fault, an extremely fast acting and low energy let-through circuit protection device is needed. The only device available in the world to protect these sensitive devices are semiconductor fuses. .

Understanding the protection requirements and selecting the right semiconductor fuse for your application can be an overwhelming, time-consuming process even for a seasoned power electronics design engineer. An important part of developing quality overcurrent protection is understanding system needs and overcurrent protective device fundamentals.

Overload Fault Condition: Defined as an overcurrent that is confined to the normal current path, which if allowed to persist in the circuit, will cause damage to equipment and/or any connected wiring. Overcurrent protective devices must disconnect circuits and equipment experiencing continuous overloads before any overheating occurs.
Short-Circuit Fault Condition: An overcurrent that flows outside its normal current path in the circuit is a short-circuit fault condition. A short-circuit fault is most commonly caused by an insulation breakdown or a faulty connection. When a short-circuit fault occurs, the current bypasses the normal load and takes a shorter path, hence the term short-circuit.

Performance capabilities of semiconductor fuses are determined in the form of various characteristic curves where two or more electrical performances are compared and represented graphically. Typical semiconductor fuse characteristic curves include: