USBUFXXW6_06 Datasheet, PDF (1/11 Pages) STMicroelectronics – EMI filter and line termination for USB upstream ports

A. S. D.
USBUFxxW6
EMI filter and line termination for USB upstream ports
Application
EMI Filter and line termination for USB upstream
ports on:
■ USB Hubs
■ PC peripherals
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
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).
Benefits
■ 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
SOTT323-6L
Table 1. Order Codes
Part Number
USBUF01W6
USBUF02W6
Marking
UU1
UU2
Figure 1. Functional diagram
3.3 V
Rt
Rp
D1
D4
Ct
Grd
3.3 V
Rt
D2
D3
Ct
CODE 01
CODE 02
Tolerance
Rt
33 Ω
22 Ω
± 10%
Rp
1.5 kΩ
1.5 kΩ
± 10%
Ct
47 pF
47 pF
± 20%
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
www.st.com
11