Semtech ESD Protection of USB 2.0 Interface Devices

ESD is the transfer of electrostatic energy between the host and peripherals that may occur when the user plugs and unplugs USB devices. This action may lead to an ESD event reaching thresholds of tens of thousands of volts. ESD can damage the delicate internal circuitry of the host or peripheral transceiver. Placing a transient-voltage-suppression (TVS) diode between the USB port and the USB controller provides ESD protection.

There are two common configurations employed to protect the USB 2.0 port from ESD threats. The user can use separate discrete TVS diodes to protect the V_BUS and D+/D- lines separately, or use an integrated TVS array in a single chip to protect all three lines.

Using discrete TVS diodes to protect USB 2.0 interfaces, the Semtech µClamp^®0571P meets all criteria and is a worthy candidate to protect the USB 2.0 V_BUS pin. µClamp0571P features a 5V operating voltage with a high surge peak current capability of 80A. It comes in a 1.6mm x 1.0mm x 0.5mm package size. The image below shows the connection diagram of TVS protection at the USB 2.0 port.

The Semtech RClamp^®0582B, a dual-channel device, can be used to protect D+ and D- lines. RClamp0582B provides transient protection as specified in IEC 61000-4-2 (ESD) at ±30kV (Air) and ±30kV (Contact). Semtech builds it in the industry-standard SOT-523 package. The maximum junction capacitance of RClamp0582B is extremely low at 1.2pF and offers a dynamic resistance of 0.52Ω (typ.).

When using a single TVS diode to protect USB 2.0 interfaces, the Semtech RClamp7522T is a 5V TVS protection solution for the V_BUS and D+/D- pins. The RClamp7522T has a maximum capacitance of 0.4pF between any line and ground and is rated to withstand ±25kV (Air) and ±15kV (Contact). This specification meets the IEC 61000-4-2 standard and offers a 5-pin package with a nominal dimension of 1.0mm x 0.7mm x 0.4mm. The following diagram shows the TVS protection connection between the USB 2.0 port and the controller.

EMI is the interference in the operation of an electrical circuit caused by emissions in the radio frequency (RF) spectrum from an external source. An EMI filter avoids EMI interference by eliminating unwanted RF noise while maintaining signal integrity.

The Semtech EClamp^®8052P is an exceptional solution to protect D+ and D- lines against ESD and EMI in USB 2.0 interfaces. It uses a 2-line integrated common-mode filter and an ESD protection device. The integrated common-mode filter typically has a differential-mode cutoff frequency above 3GHz. EClamp8052P also features the typical common mode suppression of 10dB at 500MHz and 15dB from 1GHz to 2.8GHz. It has a maximum channel capacitance of 1.2 pF and is rated to withstand ±30kV (Air) and ±25kV (Contact) per the IEC 61000-4-2 specification.

The USB 2.0 interface is still immensely popular among consumers and in non-handheld industrial, medical, and storage devices. An average person connects at least three to four peripheral devices the user's computer every day using USB 2.0 interfaces. Protecting the USB 2.0 ports from disastrous ESD events is mandatory. No user would like to experience damage to electronic equipment due to an ESD event triggered through the USB interface.

Semtech's wide range of TVS diodes protects many of the world's most popular electronic devices. Its highly efficient and trusted TVS products protect all types of USB interfaces, including USB 2.0. The user can enjoy glitch-free, problem-free data transmission by protecting USB 2.0 ports with Semtech TVS diodes, while also enhancing the reliability and longevity of the protected devices.