September 2006

Rev 3

1/11

11

USBDFxxW5

EMI filter and line termination for USB downstream ports

Applications

EMI Filter and line termination for USB

downstream ports on:

Features

termination for USB downstream ports

bypassing capacitors.

Description

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

a very small (50% smaller than the standard

SOT23).

Complies with the following standards

Functional diagram

Order codes

Benefits

ports

IEC61000-4-2 level 4

the design of high density boards

TM: IPAD is a trademark of STMicroelectronics

IEC 61000-4-2, level 4 ±15 kV (air discharge)

±8 kV (contact discharge)

MIL STD 883C, Method 3015-6

Class 3 C = 100 pF R = 1500 W

3 positive strikes and 3 negative strikes (F = 1 Hz)

Part number

Marking

USBDF01W5

UD1

USBDF02W5

UD2

SOT323-5L

D+ In

D- In

Gnd

D+ Out

D- Out

Rt

Rd

Ct

Rt

Ct

Rd

USBDF01W5

33

Ω

15 k

Ω

47 pF

USBDF02W5

15

Ω

15 k

Ω

47 pF

Tolerance

±10%

±10%

±20%

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