New Industry Products

Alpha and Omega Semiconductor Debuts a Series of High-Speed TVS Diodes

June 28, 2021 by Gary Elinoff

The new single-channel, bidirectional Transient Voltage Suppressors (TVS) provide ESD protection for USB Type-C applications

The AOZ8S303BLS-24 and AOZ8S305BLS-24 from Alpha and Omega Semiconductor (AOS) offer low clamping voltage, low capacitance and high trigger voltage, affording electrostatic discharge (ESD) protection for high speed data lines 

USB Type-C with Power Delivery (PD) is now a standard offering in modern electronic devices. They operate over a voltage range from 5 to 20 volts, but traditional TVS diodes typically feature breakdown voltages well below this level. This can result in the diode being unnecessarily damaged or shorted. The high reverse working voltage of the AOZ8S303BLS-24 and the AOZ8S305BLS-2 covers the entire voltage range of the new USB ports, avoiding this hazard.

Reactions to transmission line pulses (TLP). Image courtesy of AOS
Reactions to transmission line pulses (TLP). Image courtesy of AOS

Both TVS devices present exceptionally low junction capacitances that are necessary for any device that straddles a high-speed data line. This vital specification renders the AOZ8S303BLS-24 and the AOZ8S305BLS-24 well suited for the challenges presented by modern high-speed applications such as USB, Thunderbolt, HDMI, and PCI Express 


The Challenges Posed by USB Type-C

As stated by Michael K. S. Ng, Sr. Marketing Manager of the TVS product lineat AOS, “Type-C connectors are widely applied in electronics devices. The new products housed in a standard WLCSP0 6 x 0.3-2 (0201) package, and its small form factor is ideal for high-speed differential signals in Type-C. Both AOZ8S303BLS-24 and AOZ8S305BLS-24 will not only contribute to reducing the ESD failure rate but also reducing the failure of Short-to -VBUS in our partners’ and customers’ electronic products.” 


Common Features

Both devices feature maximum reverse working voltage of 24 Volts, hence the suffix. Their tiny 0.6 x 0.3 mm size render them well suited to providing ESD protection in applications where board space is at a premium. 


The AOZ8S303BLS-24

The AOZ8S303BLS-24 features a maximum peak pulse current of 9 amps. The typical clamping voltage is 6 volts, and the device’s typical junction capacitance is 0.20pF

Important ESD features include:

  • IEC 61000 4-2, ESD immunity:
    • Air discharge: ±20 kV
    • Contact Discharge: ±20 kV
  • IEC 61000-4-5 (Lightning 8/20 µs): 9 amps
  • Human Body Mode: ±8 kV


The AOZ8S305BLS-24 

The AOZ8S305BLS-24 features a higher maximum peak pulse current of 20 amps, and the junction capacitance is higher, too, at 0.50pF. The clamping voltage here is 4 volts (typ).

For this TVS diode, the ESD figures are:

  • IEC 61000 4-2, ESD immunity
  • Air discharge: ±30 kV 
  • Contact Discharge: ±30 kV 
  • IEC 61000-4-5 (Lightning 8/20 μs): 20 amps
  • IEC 61000-4-4 EFT (5/50 ns): 80 amps
  • Human Body Mode: ±8 kV 



  • USB4
  • USB 2.0 and 3.2, Thunderbolt, PCI Express
  • Notebook computers
  • Mobile phones
  • Portable devices



  • The TVS diodes operate over a -40 to +125°C junction temperature range
  • They are available in WLCSP 0.6 x 0.3-2 packages 



  • Both devices are RoHS compliant