Welcome to Findchips Finds: a new article series where we examine specific parts that are showcasing volatile demand, lead times, or pricing.
In this article, we’ll take a deep dive into the STMicroelectronics USBLC6-2SC6, and why it’s the ideal ESD Protection Diode for USB 2.0 reference designs.
What Is the Best ESD Protection Diode for USB 2.0 Data Lines?
Design engineers should use the STMicroelectronics USBLC6-2SC6 as the default ESD protection for USB 2.0 D+ and D- signal lines. It meets IEC 61000-4-2 Level 4 with less than 1 pF of capacitance per line, low enough to leave USB 2.0 signal integrity intact. And it has adequate stock and lead time. Compare USBLC6-2SC6 pricing and stock across distributors now.
Published April 2026 | 5 min read | Updated from Supplyframe Design Activity
Next step: Check USBLC6-2SC6 availability across distributors.
Why the USBLC6-2SC6 Is the Standard Choice
The USBLC6-2SC6 because it is a compact dual-line solution that protects both USB 2.0 data lines without degrading the 480 Mbps signal eye. USB 2.0 Hi-speed is fast enough that any protection component with too much parasitic capacitance rolls off the signal and causes eye diagram failures. The USBLC6-2SC6 solves this with a dual rail TVS array in a single SOT-23-6 package.
Here’s why this is the default choice in most USB 2.0 reference designs:
- Capacitance: 0.85 pF typical per I/O line, well under the 1 pF threshold where USB 2.0 signal quality starts to degrade
- Clamping voltage: 7V per rail, safely within the tolerance of the 3.3V USB 2.0 data lines
- IEC 61000-4-2 Level 4: withstands 8 kV contact discharge and 15 kV air discharge, the highest commercial ESD rating
- Package: SOT-23-6, small enough to place within the connector keepout zone where it does the most good
- One part, two lines: the dual rail layout protects both D+ and D- simultaneously
Next step: Check USBLC6-2SC6 authorized stock now.
Key Specifications
Engineers spec comparing the USBLC6-2SC6 against alternates should focus on capacitance per I/O and clamping voltage, which are the two parameters that determine whether a TVS array will work for USB 2.0.
| Parameter | Value |
| Manufacturer | STMicroelectronics |
| Part Number | USBLC6-2SC6 |
| Package | SOT-23-6 |
| Protected Lines | 2 (D+ and D-) |
| Standoff Voltage | 5.25V |
| Clamping Voltage | 7V at 16A peak pulse |
| Capacitance per I/O | 0.85 pF typical |
| ESD Rating (IEC 61000-4-2) | Level 4, 8 kV contact, 15 kV air |
| Operating Temperature | Negative 40C to positive 125C |
| RoHS | Yes |
Next step: View USBLC6-2SC6 datasheet and distributor stock.
PCB Placement: Where and How
Place the USBLC6-2SC6 within 200 mil of the USB connector pins, before any other component on the D+ and D- traces. Placement is as important as part selection. A diode placed 2 inches from the connector provides far less protection than one placed within 100 mil of the connector pins, because the charge must reach the diode before it reaches any other trace.
Keep these placement rules in mind:
- Place the USBLC6-2SC6 between the USB connector and everything else on the board
- Keep the diode within 200 mil (5 mm) of the USB connector pins
- Avoid vias between the connector and the diode, since vias add inductance that slows the clamping response
- Place the ESD diode inline at the connector entry and route D+ and D− as a 90 Ω differential pair with minimal stub length to the protection device.
- Pour a solid ground plane under the diode for thermal relief and low impedance ground return
Next step: Check USBLC6-2SC6 stock before finalizing PCB layout.
When to Use an Alternative
The USBLC6-2SC6 is correct for USB 2.0. For higher speed USB or automotive use, engineers should design in a different part from the start rather than retrofit.
| Standard | Recommended Part | When to Use | Check Availability |
| USB 3.0 / 3.1 SuperSpeed (up to 10 Gbps) | PRTR5V0U2X (Nexperia) or TPD2E2U06 (Texas Instruments) | Capacitance must be below 0.3 pF | Check PRTR5V0U2X availability |
| USB C with Power Delivery | USBLC6-2SC6 for data lines plus dedicated USB C CC pin protection IC | Full port protection stack | Check USBLC6-2SC6 availability |
| Automotive USB (AEC-Q101) | USBLC6-2SC6Y | Requires AEC-Q101 qualification | Check USBLC6-2SC6Y availability |
Next step: Compare PRTR5V0U2X pricing for USB 3.0 designs.
Where to Buy the USBLC6-2SC6
Engineers and buyers should source the USBLC6-2SC6 from authorized distributors to guarantee authenticity and RoHS compliance. The part is stocked in high volume worldwide and is available in tape and reel (USBLC6-2SC6Y suffix) for SMT production.
Next step: Compare USBLC6-2SC6 real time stock across Digi Key, Mouser, Arrow, Avnet, TTI, and 50+ authorized sources.
Frequently Asked Questions
| Question | Answer |
| What package does the USBLC6-2SC6 come in? | SOT-23-6. A slightly larger SOT-323-6 (SC-70-6) footprint is available depending on the suffix. Check USBLC6-2SC6 package options. |
| Can the USBLC6-2SC6 protect USB 3.0 SuperSpeed lines? | Not recommended. USB 3.0 runs at up to 5 Gbps, and the USBLC6-2SC6 0.85 pF capacitance is too high and will degrade the signal eye. Use the PRTR5V0U2X instead. Check PRTR5V0U2X stock. |
| What is the clamping voltage? | 7V typical clamping under IEC ESD conditions Check USBLC6-2SC6 stock. |
| Does it protect the VBUS line? | No. The USBLC6-2SC6 protects only D+ and D- data lines. VBUS requires separate protection, typically a TVS diode rated for 5V standoff such as the SMAJ5.0A. Check SMAJ5.0A stock. |
| Is it RoHS compliant? | Yes. All standard USBLC6-2SC6 variants are RoHS 2 compliant. Check USBLC6-2SC6 stock. |
Next step: Check USBLC6-2SC6 authorized stock before PCB release.