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Littelfuse have a long and successful history of providing industry leading circuit protection devices, not only for primary and secondary protection of power supplies but also for the sensitive I/O’s found on many modern devices including USB ports which can be susceptible to damage caused by a range of common electrical hazards. These I/O ports can typically be exposed to electrostatic discharge (ESD), lightening surges, induced power surges, electrical fast transients (EFT), miswiring or damage to cable insulation or incorrect connections by the end user. With such a wide range of possible hazards that can damage the I/O ports and lead to failure of equipment, it’s a huge challenge for today’s product developer as they seek to ensure all of these possible hazards are taken into account during the design phase to make the end device is as robust as possible against these and any other unforeseen events.

One of the most common I/O ports found on many modern devices is the ubiquitous USB port, the USB port is designed to transfer data at very high speed and can also handle power delivery to and from a device, for example charging a mobile phone. The USB standard is constantly evolving as user demand increases for higher data transfer speeds, higher power handling capability and a common standard which allows use of charging and data transfer cables across multiple devices.

Littelfuse have a range of devices which are suitable for protecting USB ports from these common electrical hazard events, the following block diagrams demonstrate how these devices can be configured to ensure robust protection for your USB ports along with an overview of each device used and its function.

Device I – Low Rho series Resettable PolySwitch PPTC

The Low Rho Resettable PPTC (Polymer Positive Temperature Coefficient) series provides overcurrent protection for applications where ultra-low internal resistance, ultra-low voltage drop and automatic resettable protection are desired such as on the 5 VDC power supply in the USB controller. The Low Rho series allows a higher hold current device in a smaller factor and lower profile as compared to a standard PPTC. It offers ultra-low internal resistance while maintaining the high level electrical characteristics and performances of standard PPTC products. All devices are UL recognized and TUV approved and have maximum fault current of 50A. They are available in 0402 to 2920 sizes while the hold current ranges from 100mA to 9A.

Device II – SP3019 and SP3400 series Diode Arrays

The SP3019 integrates 4 channels of ultra-low capacitance asymmetrical protection in a SOT23-6L package whilst the SP3400 integrates 2 channels of low capacitance steering diodes and an additional zener diode in a μDFN-6 package measuring just 1.60 x 1.0mm, both devices provide protection for USB data lines and electronic equipment that may experience destructive electrostatic discharges (ESD) by clamping transient to a safe level preventing catastrophic failure. The SP3019 and SP3400 series are compact and very robust components that can safely absorb repetitive ESD strikes above the maximum contact level specified in the IEC 61000-4-2 international standard (±8kV contact discharge) without performance degradation. The low off-state capacitance also make these devices suitable for protecting high speed signal lines in other applications such as HDMI, eSATA and 1Gb Ethernet ports.

Device III – SP3213 series Bidirectional TVS Diode

The SP3213 is a bidirectional TVS Diode that provides ultra-low capacitance and a high level of protection for USB data lines and electronic equipment that may experience destructive electrostatic discharges (ESD) by clamping transient to a safe level preventing catastrophic failure. The typical capacitance of 0.09pF helps ensure signal integrity on USB ports and other challenging consumer electronics interfaces such as HDMI 2.1, 2.0, DisplayPort, Thunderbolt, and V-by-One®. The SP3213 is supplied in a compact μDFN-2 (0201) package measuring just 0.60 x 0.30mm, the device can safely absorb repetitive ESD strikes at ±12kV (contact discharge, IEC 61000-4-2) without performance degradation and safely dissipate 2A of 8/20μs surge current (IEC 61000-4-5 2nd edition).

Device IV – SP1006 series Unidirectional TVS Diode

The SP1006 series are zener diodes fabricated in a proprietary silicon avalanche technology designed to protect each pin on an I/O port providing a high level of protection for USB power lines and other electronic equipment that may experience destructive electrostatic discharges (ESD) by clamping transient to a safe level preventing catastrophic failure. The SP1006 is supplied in a μDFN-2 (0201) package measuring just 0.60 x 0.30mm, these compact and robust diodes can safely absorb repetitive ESD strikes at ±30kV (contact discharge, IEC 61000-4-2) without performance degradation. Additionally, each diode can safely dissipate 5A of 8/20μs surge current (IEC 61000-4-5, 2nd Edition) with very low clamping voltages.

Device V – SPHV series Unidirectional TVS Diode

The SPHV series of unidirectional TVS diodes are ideal for use in portable applications such as power bus and charge controller protection in USB ports, other suitable applications include LED lighting modules, automotive applications, and low speed I/Os. The device will protect sensitive equipment from damage due to electrostatic discharge (ESD) and other overvoltage transients by clamping transient to a safe level preventing catastrophic failure. The SPHV series is supplied in a compact SOD882 package measuring 1.0 x 0.60mm, the devices can safely absorb repetitive ESD strikes above the maximum level of the IEC 61000-4-2 international standard (Level 4, ±8kV contact discharge) without performance degradation and safely dissipate up to 8A (SPHV12) of induced surge current (IEC 61000-4-5, 2nd Edition tP=8/20μs) with very low clamping voltages.

Device VI – setP™ series Temperature Indicator

The Littelfuse setP™ series temperature indicator helps protect USB Type-C plugs and cables from overheating. It has been designed to the unique specifications of USB Type-C and is capable of helping to protect even the highest levels of USB Power Delivery in systems with 100W or higher power ratings. These compact SMD devices are supplied in an industry standard 0805 package and offer sensitive and reliable temperature indication.

Device VII – SP3530 Unidirectional TVS Diode

The SP3530 series unidirectional diode provides a high level of protection for USB data lines and other electronic equipment that could be exposed to the risk of electrostatic discharges (ESD) and overvoltage transients by clamping transient to a safe level preventing catastrophic failure. The SP3530 series is supplied in a compact SOD882 package measuring 1.0 x 0.60mm, the robust component can safely absorb repetitive ESD strikes above the maximum level specified in the IEC 61000-4-2 international standard (±8kV contact discharge) without performance degradation. The extremely low loading capacitance also make these devices ideal for protecting other high speed ports such as V-By-One®, HDMI, LVDS, DisplayPort™ and IEEE 1394 interfaces.

These protection devices from Littelfuse all offer robust protection for USB ports and other applications that use high speed signal/data and power lines including Imaging equipment, Battery packs, Displays, Entertainment devices, Communication & Network equipment, Data Storage, Test equipment, Instrumentation, Consumer devices, Wearables, IoT devices, Industrial and Medical equipment.

Anglia are offering customers FREE samples of protection diodes, temperature indicators and resettable PPTC devices suitable for protecting USB ports from Littelfuse, please fill in the form below to register for samples now.