1/9

USBUFxxW6

®

EMI FILTER AND LINE TERMINATION

FOR USB UPSTREAM PORTS

March 2002 - Ed: 3A

A.S.D.

™

SOT323-6L

FUNCTIONAL DIAGRAM

TM: ASD and TRANSIL are a trademarks of STMicroelectronics.

EMI Filter and line termination for USB upstream

ports on:

- USB Hubs

- PC peripherals

APPLICATIONS

s

Monolithic device with recommended line termi-

nation for USB upstream ports

s

Integrated Rt series termination and Ct bypass-

ing capacitors.

s

Integrated ESD protection

s

Small package size

FEATURES

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 IEC61000-4-2 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).

DESCRIPTION

s

EMI / RFI noise suppression

s

Required line termination for USB upstream

ports

s

ESD protection exceeding IEC61000-4-2 level 4

s

High flexibility in the design of high density

boards

s

Tailored to meet USB 1.1 standard

BENEFITS

3.3 V

Rp

Ct

Rt

Ct

Rt

D1

Grd

D2

D4

D3

3.3 V

Rt

Rp

Ct

CODE 01

33

Ω

1.5k

Ω

47pF

CODE 02

22

Ω

1.5k

Ω

47pF

Tolerance

±10%

±10%

±20%