September 2006 Rev 3 1/11
11
USBDFxxW5
EMI filter and line termination for USB downstream ports
Applications
EMI Filter and line termination for USB
downstream ports on:
■ Desktop computer
■ Notebooks
■ Workstations
■ USB Hubs
Features
■ Monolithic device with recommended line
termination for USB downstream ports
■ Integrated Rt series termination and Ct
bypassing capacitors.
■ Integrated ESD protection
■ 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
a very small (50% smaller than the standard
SOT23).
Complies with the following standards
Functional diagram
Order codes
Benefits
■ EMI / RFI noise suppression
■ Required line termination for USB downstream
ports
■ ESD protection exceeding
IEC61000-4-2 level 4
■ IPAD™ technology provides high flexibility in
the design of high density boards
■ Tailored to meet USB 1.1 standard
TM: IPAD is a trademark of STMicroelectronics
IEC 61000-4-2, level 4 ±15 kV (air discharge)
±8 kV (contact discharge)
MIL STD 883C, Method 3015-6
Class 3 C = 100 pF R = 1500 W
3 positive strikes and 3 negative strikes (F = 1 Hz)
Part number Marking
USBDF01W5 UD1
USBDF02W5 UD2
SOT323-5L
D+ In
D- In
Gnd
D+ Out
D- Out
Rt
Rd
Ct
Rt
Ct
Rd
R
t
R
d
C
t
USBDF01W5 33 Ω 15 kΩ 47 pF
USBDF02W5 15 Ω 15 kΩ 47 pF
Tolerance ±10% ±10% ±20%
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