L-USS820D-DB LSI, L-USS820D-DB Datasheet - Page 49

• Manufacturer Part Number: L-USS820D-DB
• Manufacturer: LSI

Specifications of L-USS820D-DB

• Operating Temperature (min): -20C
• Operating Temperature Classification: Commercial
• Operating Temperature (max): 85C
• Rad Hardened: No
• Lead Free Status / RoHS Status: Compliant

Data Sheet, Rev. 7
September 2004
Agere Systems Inc.
Electrical Characteristics
Connection Requirements
USB Transceiver Connection
The physical connection of the USS-820D to the USB
bus requires only minimal components to provide
proper USB electrical terminations.
Both DPLS and DMNS require 24 Ω ± 1% series resis-
tors for USB impedance matching. Additionally, a
1.5 kΩ pull-up resistor is required on DPLS for full-
speed/low-speed differentiation.
Figure 8. USB Transceiver Connection
+3.3 V
24 Ω ± 1%
24 Ω ± 1%
1.5 kΩ
±
0.3 V
Example for Bus-Powered
Application
±
DMNS
DPLS
5%
(continued)
5-8119
When using the USS-820D in a self-powered device,
there are some additional considerations. The device
must refrain from supplying power through the pull-up
resistor if plugged into an unpowered bus. It must also
ensure that the DPLS and DMNS lines are in an appro-
priate state when the device is powered but not
plugged in. Figure 9 shows an example connection to
meet these requirements.
Figure 9. USB Transceiver Connection
1.5 MΩ
1.5 MΩ
+3.3 V
Example for Self-Powered
Application
24 Ω ± 1%
24 Ω ± 1%
1.5 kΩ ± 5%
CLOSE SWITCH ONLY WHEN
V
±
BUS
0.3 V
USB Device Controller
IS POWERED
DMNS
DPLS
USS-820D
5-8120
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