February 2006

Rev 5

1/11

11

USBUFxxW6

A. S. D.

EMI filter and line termination for USB upstream ports

Application

EMI Filter and line termination for USB upstream

ports on:

Features

termination for USB upstream ports

bypassing capacitors.

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

ports

IEC 61000-4-2 level 4

boards

Figure 1.

Functional diagram

Complies with the following standards:

Table 1.

Order Codes

Part Number

Marking

USBUF01W6

UU1

USBUF02W6

UU2

Rt

Rp

Ct

CODE 01

33

Ω

1.5 k

Ω

47 pF

CODE 02

22

Ω

1.5 k

Ω

47 pF

Tolerance

± 10%

± 10%

± 20%

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)

SOTT323-6L

3.3 V

Rp

Ct

Rt

Ct

Rt

D1

Grd

D2

D4

D3

3.3 V

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