The USB Type-C interface standard defined by USB-IF was rapidly and widely adopted by both the consumer market and industry after its introduction. Featuring a compact form factor and reversible plug orientation, USB Type-C supports not only high-speed data transmission but also power delivery. Mainstream devices supporting the PD 3.1 specification can deliver up to 48 V / 5 A. For data transmission, USB Type-C supports speeds up to USB4 80 Gbps and is also compatible with DisplayPort (DP) and other audio/video signals.
USB Type-C offers advantages such as a compact size (only 8.6 mm × 2.6 mm) and a high level of functional integration. However, its dense 24-pin design also introduces potential risks, as illustrated in Figure 1. In real-world use, the very small pin-to-pin spacing can result in shorts, misalignment, or accidental contact. The most serious risk occurs when VBUS is at 28 V DC and accidentally contacts a CC or SBU pin, whose normal operating voltage is approximately 5 V or 3.3 V. Such an event may burn out the downstream IC or damage the TVS device.
Figure 1. Illustration of USB Type-C Port Pin Shorting
Therefore, USB Type-C interface protection must address not only ESD (electrostatic discharge) and EOS (electrical overstress), but also system safety in the event of accidental VBUS-to-CC/SBU contact.
To address this failure mode, many consumer-electronics brands now require a DC withstand-voltage test on the CC and SBU ports, applying 28 V DC to verify product reliability. A common design approach is to place a TVS diode near the USB Type-C connector and use a downstream PD controller with integrated OVP (overvoltage protection) to improve overall protection.
However, a conventional TVS with VRWM = 5 V cannot pass the 28 V DC withstand-voltage test. Using a TVS with VRWM ≥ 28 V solves the DC withstand issue, but its higher clamping voltage (VCL) reduces ESD/EOS protection performance and may even lower the pass rate of system-level ESD tests such as Pin Injection. Consequently, demand is increasing for TVS solutions that combine high DC withstand capability with low clamping voltage.
To meet this application requirement, Amazing Microelectronic Corp. has introduced the AZ5H45-01B dedicated protection device, as shown in Figure 2. Unlike a conventional 5 V TVS, the AZ5H45-01B is designed with a reverse breakdown voltage (VBV) above 32 V, ensuring that it does not turn on during a 28 V DC test and avoiding device damage caused by sustained energy. At the same time, its clamping voltage under an 8 kV ESD event is only about 10 V, helping the system pass ESD testing. In addition, the device provides 6.5 A surge capability (8/20 μs, IEC 61000-4-5), delivering robust EOS protection for the system.
Figure 2. AZ5H45-01B Dedicated Protection Device for USB Type-C CC/SBU
The key to the AZ5H45-01B’s low clamping voltage is its approximately 6 V snap-back holding voltage (Vhold) after turn-on. This characteristic lowers the clamping voltage without disturbing the CC/SBU signals, while also reducing latch-up risk. Amazing Microelectronic Corp. specifies the device as VRWM = 5 V, helping engineers avoid misinterpretation during component selection and improve design safety.
For packaging, the AZ5H45-01B uses an ultra-compact 0201 package, providing high layout flexibility and supporting ongoing device miniaturization. For full-featured USB4 applications, Amazing Microelectronic Corp. also provides a complete protection solution, including the ultra-low-capacitance AZ5B9S-01F TVS for high-speed signal lines, the AZ5H45-01B for CC/SBU lines with DC withstand-test capability, and the AZ4528-01F / AZ4728-01F for high-surge protection on VBUS.
As USB Type-C becomes more widely adopted across increasingly diverse applications, device failure rates and field-return/repair rates can also rise. Therefore, system designs should consider extreme conditions such as DC withstand voltage in addition to basic ESD and EOS protection. Amazing Microelectronic Corp. offers a broad range of protection devices to help customers improve product reliability, reduce repair costs, and strengthen overall system immunity, making products more reliable and appealing to end users.