STF201-22 & STF201-30
USB Downstream Port Filter & TVS
For EMI Filtering and ESD Protection
PROTECTION PRODUCTS
Features
Description
The STF201 is a combination EMI filter and line termi-
nation device with integrated TVS diodes for use on
downstream USB ports. It is constructed using a
proprietary technology that allows passive components
and TVS diodes to be integrated in the same package.
Each device will provide termination, filtering, and ESD
protection for one downstream USB port. The STF201
is an easily implemented solution for meeting the
requirements of revision 1.1 of the Universal Serial Bus
specification.
Bidirectional EMI/RFI filtering and line termination
with integrated ESD protection
ESD protection for USB power (VBUS) and data lines
(D+ & D-) to IEC 61000-4-2 Level 4
Filtering and termination for two USB data lines
Different series resistors for impedance matching
Low TVS operating voltage (5.25V)
Low leakage current
Low capacitance
Solid-state technology
USB line termination is achieved with series 22Ω or
30Ω resistors on both the D+ and D- USB lines. These
resistors preserve signal integrity by matching the cable
impedance to that of the differential driver. The 15kΩ
pull-down resistors complete the termination circuit on
each line. They are required by the USB specification
to identify the line as a downstream connection. The
47pF capacitors are used to bypass high frequency
energy to ground and for edge rate control of the USB
signals. Finally, the STF201 contains TVS diodes for
ESD protection of both (D+ & D-) data lines and the
voltage bus (VBUS). The TVS diodes provide effective
suppression of ESD voltages in excess of 15kV (air
discharge) and 8kV (contact discharge) per IEC 61000-
4-2, level 4.
Mechanical Characteristics
EIAJ SOT23-6L package
Molding compound flammability rating: UL 94V-0
Marking : Marking Code
Packaging : Tape and Reel per EIA 481
Applications
USB Hubs
Portable electronics
Printers
Monitors
Servers, Desktop, and Notebook computers
The small size and integrated feature of the STF201
minimizes required board space and increases system
reliability. The pin-out of the device allows easy imple-
mentation. The STF201 is suitable for use in USB
hubs, computers, peripherals, and portable devices.
Circuit Diagram
Pin Configuration
S0T23-6L (Top View)
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Revision 08/11/04