USBUF01W6 View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

USBUF01W6

EMI FILTER AND LINE TERMINATION FOR USB UPSTREAM PORTS

STMicroelectronics 

USBUFxxW6

TRANSITION TIMES

This low pass filter has been designed in order to meet the USB 1.1 standard requirements that implies the

signal edges are maintained within the 4ns-20ns stipulated USB specification limits. To verify this point, we

have measured the rise time of VD+ voltage (please refer to Fig. A13) with and without the USBUFxxW6

device.

Fig. A13: Typical rise and fall times: measure-

ments configuration

Fig. A14: Typical rise times with and without pro-

tection device

Square

Pulse

Generator

+5V

74HC04

D+

+5V

D-

+5V

74HC04

USBUF

-xxW6

+5V

VD+

without

with

Figure A13 shows the circuit used to perform measurements of the transition times. In Figure A14, we see

the results of such measurements:

trise = 3.8ns driver alone

trise = 7.8ns with protection device

The adding of the protection device causes the rise time increase of roughly 4ns.

Note: Rise time has been measured between 10% and 90% of the signal (resp. 90% and 10%)

8/9

Share Link: