Eaton fuses and other components

Cylindrical fuses are still among the most common solutions for protecting circuits of industrial machines and consumer appliances (consumer electronics, white goods) ‒ they can be found in many types of power supplies, converters and other power modules. Eaton offers such components in many popular sizes, including with diameters of 5 mm and 6.3 mm, and lengths from 8.7 mm to 32.6 mm. They come in glass and ceramic versions (filled with sand to eliminate the risk of arcing when the fuse blows). Their design allows them to protect circuits operating not only at typical mains voltages (250 V AC), but even up to 1 kV AC and 600 V DC (depending on the model). The manufacturer supplies time-lag, medium time-lag, quick blow and ultra rapid fuses ‒ you can choose the right component for your needs, depending on the specific load, occurrence of increased inrush currents, etc. The rated currents of these fuses range from 5 mA to 63 A, with a breaking capacity that for some series reaches 30 kA at AC and 50 kA at DC.

The most ‘standard’ variant of the cylindrical fuse, in a glass tube.

TR5 housing provides a way for a fuse to be soldered into the PCB circuit.

TR5 fuses are used in PCB circuits primarily to protect mains-powered circuits (Eaton fuses are designed for 125 V, 250 V and 300 V AC). Their advantages include a small footprint and the possibility to be mounted directly on the PCB ‒ they have leads for through-hole mounting (THT) at a typical terminal pitch of 5.08 mm. In the TME catalogue, you can purchase such fuses in bulk or in Ammo Packs. The available models are characterised by current ratings from 0.4 A to 10 A (breaking capacity up to 100 A). You can choose between quick blow or time-lag fuses.

The TE5 is a rectangular fuse format for mounting directly in PCB circuits, similar in volume to the TR5 cylindrical elements described above (they have the same terminal pitch, i.e. 5.08 mm). Similarly, TE5 fuses also come in quick blow and time-lag versions for use with mains voltages (125 V to 350 V AC). The products of this kind are primarily used in consumer equipment circuits, e.g. battery chargers, power supplies/converters, but are also sometimes used in industrial applications. Selected TE5 fuse models from Eaton additionally have a wide thermal tolerance in the range of -40°C to 125°C.

TE5 is one of the smallest THT fuse sizes.

The fuse can be placed in a holder or soldered directly onto a PCB.

The popularity of SMD fuses has increased with the miniaturisation of battery-powered devices, partly due to the small size of the components themselves, but also because of the very high currents that the most common types of cells (lithium-polymer and lithium-ion) can deliver. For this reason, protection is required not only for converter and charger circuits, but also for balancers and even the PCBs themselves: even a relatively small battery is capable of burning through the fine traces of a multilayer PCB. SMD fuses are available from the Eaton range in a number of standard packages, such as: 0603, 1206, 2410 or UM (typically used for mounting in special holders). Despite their small size, selected models are designed to handle voltages up to 350 V AC and 600 V DC and rated currents up to 125 A (from 250 mA). Similarly to the larger components, this group also includes time-lag and quick blow fuse versions.

Varistors are commonly used in combination with fuses to protect circuits against voltage spikes. Their non-linear resistance is used in both DC and AC circuits. The miniature varistors from Eaton are manufactured in SMD packages ranging from 0402 to 4032. The varistors can operate at voltages from 16 V to 240 V and are capable of handling current peaks of even 1.2 kA (selected models).

Miniature SMD varistor in a 1210 package

Selected Eaton resistors are designed for use in automotive electronics.

Eaton precision resistors have a tolerance of ±1%. They make it possible to manufacture high-precision circuits, which makes them ideal for use in circuits with voltage regulators, A/D and D/A converters, operational amplifiers, dividers, etc. As surface-mount resistors of even 3 W can be purchased from the TME catalogue, there are also additional components that can be used in more demanding circuits, such as in motor controllers. It is also worth noting that some of Eaton’s products are manufactured in compliance with the AEC-Q200 standard, meaning they can be used in automotive applications. The thermal tolerance (which can reach up to 170°C) and a temperature coefficient of 50 ppm/°C are also noteworthy.

Similarly to the resistors described above, Eaton anti-interference filters were also designed with automotive applications in mind: primarily to protect the circuits of the CAN communication bus that are normally used in motor vehicles. They can also be applied in engine control units (ECUs) and electric power steering systems (EPSs). The inductive filters are designed to operate at voltages up to 50 V or 80 V and in a wide temperature range (from -40°C to 105°C). Their durability, wide selection of diverse parameters and compact dimensions also allow them to be used in BMSs, i.e. for energy management in multi-cell batteries.

Some of the advantages of the filters are their compact size and the possibility of surface mounting.

Eaton thermistors are manufactured in standard THT packages.

In the control of cell batteries, temperature monitoring is a very important factor. This is especially true when it comes to applications in which high-capacity and lithium-polymer batteries are used. Thermal conditions must also be taken into account in the case of energy recovery systems where supercapacitors are used. For such applications, Eaton has designed special NTC thermistors (i.e. with a negative temperature coefficient) with a tolerance of ±1%. They are suitable for operating temperatures from -40°C to 125°C and exhibit a (nominal) resistance of 10 kΩ or 100 kΩ. THT leads allow them to be positioned close to cells or other monitored objects (when connected by wires).