USBUFxxW6
A. S. D.
EMI filter and line termination for USB upstream ports
Application
EMI Filter and line termination for USB upstream
ports on:
■
■
USB Hubs
PC peripherals
SOTT323-6L
Features
■
■
■
■
Monolithic device with recommended line
termination for USB upstream ports
Integrated Rt series termination and Ct
bypassing capacitors.
Integrated ESD protection
Small package size
Table 1.
Order Codes
Marking
UU1
UU2
Part Number
USBUF01W6
USBUF02W6
Description
The USB specification requires upstream ports to
be terminated with pull-up resistors from the D+
and D- lines to Vbus. 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 USBUFxxW6 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 SOT323-6L which is
the smallest available lead frame package (50%
smaller than the standard SOT23).
Figure 1.
Functional diagram
3.3 V
Rt
Rp
D4
Ct
D1
Grd
3.3 V
Rt
D2
Ct
D3
Rt
CODE 01
CODE 02
33
Ω
22
Ω
± 10%
Rp
1.5 kΩ
1.5 kΩ
± 10%
Ct
47 pF
47 pF
± 20%
Benefits
■
■
■
■
■
Tolerance
EMI / RFI noise suppression
Required line termination for USB upstream
ports
ESD protection exceeding
IEC 61000-4-2 level 4
High flexibility in the design of high density
boards
Tailored to meet USB 1.1 standard
Complies with the following standards:
IEC 61000-4-2, level 4
± 15 kV (air discharge)
± 8 kV (contact discharge)
MIL STD 883E, Method 3015-7
Class 3 C = 100 pF R = 1500
Ω
3 positive strikes and 3 negative strikes (F = 1 Hz)
February 2006
Rev 5
1/11
11
STMICROELECTRONICS [ STMICROELECTRONICS ]
