SEMTECH STF203-22.TCT

The STF203 is a combined EMI filter and line termination device with integrated TVS diodes for upstream USB ports. It is manufactured using proprietary technology that integrates passive components and TVS diodes in a single package. Each device provides termination matching, filtering, and ESD protection for one upstream USB port. The STF203 is an easy-to-implement solution that meets the requirements of Universal Serial Bus Specification Revision 1.1.

Line termination matching is achieved using series resistors on the USB D+ and D− lines. The sum of the series resistance and USB driver output impedance must be as close as possible to the 45Ω characteristic impedance of the cable (90Ω balanced) to minimize transmission line reflections. The device is available in three resistance values: 15Ω (STF203-15), 22Ω (STF203-22), and 33Ω (STF203-33). The USB specification requires a 1.5kΩ pull-up resistor to identify the device as full-speed (connected to the D+ line) or low-speed (connected to the D− line). A 47pF capacitor is required to bypass high-frequency energy to ground and control the edge rate of USB signals. The TVS diodes provide ESD protection for both data lines (D+ and D−) and the voltage bus (VBUS). TVS diodes on the I/O pins suppress ESD voltages exceeding ±15kV (air discharge) and ±8kV (contact discharge) per IEC 61000-4-2 Level 4. The TVS diode on the VBUS pin suppresses ESD discharges exceeding 25kV per IEC 61000-4-2.

• Bidirectional EMI/RFI filtering and line termination matching with integrated ESD protection
• ESD protection for USB power (VBUS) and data lines (D+ and D−), compliant with IEC 61000-4-2 (ESD) ±15kV (air), ±8kV (contact), IEC 61000-4-4 (EFT) 40A (5/50ns)
• Filtering and termination matching for one USB port
• Series resistance: 15Ω, 22Ω, and 33Ω
• Low TVS operating voltage (5.25V)
• Low leakage current
• Compact SC70-6L package
• Solid-state technology

• USB ports
• Mobile phones
• PDAs
• Pagers
• Digital cameras
• Computer peripherals
• MP3 players