NLAS7222B, NLAS7222C
APPLICATIONS INFORMATION
The low on resistance and capacitance of the NLAS7222B
provides for a high bandwidth analog switch suitable for
applications such as USB data switching. Results for the
USB 2.0 signal quality tests will be shown in this section,
along with a description of the evaluation test board. The
data for the eye diagram signal quality and jitter tests verifies
that the NLAS7222B can be used as a data switch in low, full
and high speed USB 2.0 systems.
Figures 8, 9 and 10 provide a description of the test
evaluation board. The USB tests were conducted per the
procedures provided by the USB Implementers Forum
(www.usb.org), the industry group responsible for defining
the USB certification requirements. The test patterns were
generated by a PC and MATLAB software, and were
inputted to the analog switch through USB connectors J1
(HSD1) or J2 (HSD2). A USB certified device was plugged
into connector J4 to function as a data transceiver. The high
speed and full speed tests used a flash memory device, while
the low speed tests used a mouse. Test connectors J3 and J5
provide a direct connection of the USB device and were used
to verify that the analog switch does not distort the data
signals.
Figure 8. Schematic of the NLAS7222B USB Demo Board
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