USBDFXXW5 Datasheet, PDF (1/9 Pages) STMicroelectronics – EMI FILTER AND LINE TERMINATION FOR USB DOWNSTREAM PORTS

®
A.S.D.™
USBDFxxW5
EMI FILTER AND LINE TERMINATION
FOR USB DOWNSTREAM PORTS
APPLICATIONS
EMI Filter and line termination for USB down-
stream ports on:
- Desktop computer
- Notebooks
- Workstations
- USB Hubs
FEATURES
n Monolithic device with recommended line termi-
nation for USB downstream ports
n Integrated Rt series termination and Ct bypass-
ing capacitors.
n Integrated ESD protection
n Small package size
DESCRIPTION
The USB specification requires USB
downstream ports to be terminated with
pull-down resistors from the D+ and D- lines to
ground. On the implementation of USB
systems, the radiated and conducted EMI
should be kept within the required levels as
stated by the FCC regulations. In addition to
the requirements of termination and EMC
compatibility, the computing devices are
required to be tested for ESD susceptibility.
The USBDFxxW5 provides the recommended line
termination while implementing a low pass filter to
limit EMI levels and providing ESD protection
which exceeds IEC 61000-4-2 level 4 standard.
The device is packaged in a SOT323-5L which is
the smallest available lead frame package (50%
smaller than the standard SOT23).
BENEFITS
n EMI / RFI noise suppression
n Required line termination for USB downstream
ports
n ESD protection exceeding IEC61000-4-2 level 4
n High flexibility in the design of high density
boards
n Tailored to meet USB 1.1 standard
TM: ASD and TRANSIL are a trademarks of STMicroelectronics.
May 2000 Ed : 1C
SOT323-5L
FUNCTIONAL DIAGRAM
D+ In
Gnd
D- In
Rt
Ct Rd
Ct Rd
Rt
Code 01
Code 02
Tolerance
Rt
33Ω
15Ω
±10%
Rd
15kΩ
15kΩ
±10%
D+ Out
D- Out
Ct
47pF
47pF
±20%
1/9