USB ESD Protection

Protecting USB ports from ESD Damage

Since USB is a hot insertion & removal system, USB components are subject to Electrostatic Discharge (ESD). However, USB ESD protection is not yet a specific requirement of the USB specification. State-of-the-art USB ICs are manufactured on high integration CMOS processes making them extremely sensitive to damage from the high static voltages associated with an ESD event.

Some USB hub chips are internally protected from ESD events ranging from 500V to 2kV. This may provide a false sense of security since IEC 61000-4-2 typically requires commercial equipment pass ESD immunity tests with voltages up to 15kV for air discharge and 8kV for contact discharge. Ten pulses in each polarity are required for each test level. The IEC specification allows all cables to be attached to the equipment during testing. As such, the equipment may pass certain regulatory tests with the shielded USB cable attached.

However, by definition USB is a hot plugging bus. When the socket is open, it is vulnerable to a potentially hazardous strike. The user may inject the strike while plugging and unplugging a peripheral device, or by just reaching for a nearby switch. Physical contact with the port is not necessary. An air discharge event can occur several centimeters away from the conducting surface. Damage to the USB interface IC can occur as a result of the high static potential or from the conducted ESD currents. The resulting damage can be catastrophic or latent. Latent failures manifest themselves long after the ESD event has occurred.

> Download our "Protecting USB Ports from ESD Damage" application note

Get USB ESD Protection with industry's lowest clamping voltage

Our RailClamp® series features a range of ultra low capacitance and low clamping TVS arrays designed to offer maximum protection for your USB 1.1, 2.0, or OTG ports without degrading the integrity of your signal. This series has been specifically designed to protect sensitive components which are connected to high-speed data and transmission lines from overvoltage caused by ESD (electrostatic discharge), CDE (Cable Discharge Events), and EFT (electrical fast transients).

> Download your FREE Design Guide for:

ESD and EMI Protection Design Guide for Portable Electronics

Featured USB ESD Protection Circuits


Part Number USB Version Capacitance (pF) Package Size (LxWxH) in mm
RClamp®0502A USB 2.0 / OTG

<0.9

1.6 x 1.6 x 0.6

RClamp®0502B USB 2.0 / OTG

<1.0

1.6 x 0.8 x 0.6

RClamp®0503F USB 2.0 / OTG

<3.0

2.0 x 1.25 x 0.9

RClamp®0502N USB 2.0 / OTG

<0.4

1.2 x 1.0 x 0.58

RClamp®0503N USB 2.0 / OTG

<0.5

1.45 x 1.0 x 0.58

RClamp®0504P USB 2.0 / OTG

<3.0

1.6 x 1.6 x 0.6

STF201-22, 30 USB 1.1

60

2.9 x 1.6 x 1.15

STF202-22, 30 USB 1.1

60

2.9 x 1.6 x 1.15

STF203-15, 22, 33 USB 1.1

60

2.0 x 1.25 x 0.9

View our product selector to compare and select parts for your USB ESD protection application.