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USBDFxxW5

®

EMI FILTER AND LINE TERMINATION

FOR USB DOWNSTREAM PORTS

May 2000 Ed : 1C

A.S.D.

™

SOT323-5L

FUNCTIONAL DIAGRAM

TM: ASD and TRANSIL are a trademarks of STMicroelectronics.

EMI Filter and line termination for USB down-

stream ports on:

- Desktop computer

- Notebooks

- Workstations

- USB Hubs

APPLICATIONS

n

Monolithic device with recommended line termi-

nation for USB downstream ports

n

Integrated Rt series termination and Ct bypass-

ing capacitors.

n

Integrated ESD protection

n

Small package size

FEATURES

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

the smallest available lead frame package (50%

smaller than the standard SOT23).

DESCRIPTION

n

EMI / RFI noise suppression

n

Required line termination for USB downstream

ports

n

ESD protection exceeding IEC61000-4-2 level 4

n

High flexibility in the design of high density

boards

n

Tailored to meet USB 1.1 standard

BENEFITS

D+ In

D- In

Gnd

D+ Out

D- Out

Rt

Rd

Ct

Rt

Ct

Rd

Rt

Rd

Ct

Code 01

33

Ω

15k

Ω

47pF

Code 02

15

Ω

15k

Ω

47pF

Tolerance

±10%

±10%

±20%