STMicroelectronics USBULC6-2M6

Overview

USBULC6-2M6 from STMicroelectronics is a monolithic ultra-low-capacitance ESD protection diode array designed for high-speed USB 2.0 differential data lines (D+/D−) and optional VBUS line protection. It delivers 15 kV air/8 kV contact IEC 61000-4-2 ESD immunity, 0.65 pF typical capacitance at 240 MHz, ≤0.5 µA leakage at 5 V, and clamps to 12 V at 1 A (8/20 µs), enabling robust signal integrity in Hi-Speed USB (480 Mbps) interfaces.

For engineers reviewing the USBULC6-2M6 datasheet, USBULC6-2M6 pinout, USBULC6-2M6 application, or USBULC6-2M6 equivalent, key selection criteria include line-to-ground capacitance <0.85 pF at 240 MHz, VBUS-compatible 6 V breakdown voltage, µQFN-6 footprint compatibility, and validated eye diagram performance with 480 Mbps USB 2.0 signals.

Technical Context

The device integrates two bidirectional ESD protection diodes between D+ and GND, D− and GND, plus a dedicated VBUS-to-GND clamp-enabling simultaneous protection of both differential data lanes and power rail. Its monolithic silicon structure ensures matched capacitance (<0.02 pF variation) and low crosstalk (<−30 dB at 1 GHz), critical for maintaining differential impedance and minimizing jitter.

Designed specifically for high-bandwidth interfaces, it uses low-leakage PN junctions with fast response time (sub-nanosecond), avoiding the slower thermal activation of varistors. The 6 V breakdown voltage aligns with 5 V USB VBUS tolerance, while clamping voltages of 12 V (1 A) and 17 V (5 A) ensure downstream ICs remain within safe operating limits during ESD transients.

Key Specifications

Pinout & Package

USBULC6-2M6 is housed in a 6-pin micro QFN package (1.45 × 1.00 mm, 0.5 mm pitch) with exposed thermal pad. Pin 1 is marked by a dot; the package is RoHS-compliant and ECOPACK® certified.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar ESD protection applications.

Compared with TPD2E001DRYR and SP1001-01UTG, USBULC6-2M6 uniquely combines VBUS clamping capability, 15 kV ESD rating, and sub-0.7 pF high-frequency capacitance-making it the only single-device solution qualified for full USB 2.0 port protection including power rail integrity.

Availability

USBULC6-2M6 is available at Aetrix Electronics and suitable for USB 2.0 host/device ports, 10/100/1000BASE-T Ethernet PHY interfaces, and portable display video links requiring stable component supply and long-term production continuity.

Supply support for USBULC6-2M6 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, specializing in automotive, industrial, and consumer ICs, discrete devices, and system solutions.

The USBULC series targets high-speed interface protection, with USBULC6-2M6 engineered specifically for USB 2.0 and multi-gigabit differential signaling where signal integrity and ESD robustness must coexist.

FAQ

What is the maximum recommended PCB trace length between USBULC6-2M6 and the USB connector?

ST recommends placing the device within 3 mm of the USB connector pad to minimize inductance in the ESD current path. Longer traces increase clamping voltage due to L·di/dt effects, potentially exceeding downstream IC withstand limits. Layout guidelines in Section 5.4 emphasize symmetrical routing and closed vias to maintain controlled impedance and reduce loop area.

Does USBULC6-2M6 require external biasing or control signals?

No. USBULC6-2M6 is a passive, bidirectional ESD suppressor with no external connections beyond its six terminals. It operates solely on junction conduction during transients and draws zero static current except for inherent leakage (<0.5 µA). No enable pins, voltage references, or configuration registers are present.

Can USBULC6-2M6 be used for USB 3.0 SuperSpeed differential pairs?

No. Its 0.65 pF capacitance is optimized for USB 2.0 (up to 500 MHz), not USB 3.0 Gen1 (2.5 GHz). At 2.5 GHz, parasitic reactance would degrade signal integrity. ST recommends dedicated USB 3.0 protectors like USBLC6-2SC6 (0.25 pF) for SuperSpeed lanes.

Is the exposed thermal pad on the µQFN package required to be soldered to ground?

Yes. The exposed pad (EP) is internally connected to GND pins 2 and 5 and must be soldered to a solid PCB ground plane. This provides low-inductance ESD current return, thermal dissipation, and mechanical stability. ST specifies minimum 90% solder coverage and recommends thermal vias under the pad per JEDEC J-STD-020.