User's Manual

PW2050 Embedded Device Server Integration Guide 21
Pin Name Description PW2050
Pins
Signal Requirement RJ45 MagJack
Belfuse, 08B0-
1D1T-06-F Pin
assignment
ETXP Ethernet Transmit Positive signal. 34 100 ohm differential
pair with ETXM
2
RXCT Center tap for receive pair. 38 Route > 20 mil width 6
TXCT Center tap for transmit pair 37 Route > 20 mil width 1
Chassis Unit chassis - RJ45 connector shield Shield tabs
E_LNKACT Link / activity LED. Active low.
Solid for link, blink for activity.
72 Route to LED cathode
through 220 ohm or
greater.
9
E_SPEED Link Speed Active low for
100Mbps, Off (high) for 10Mbps.
56 Route to LED cathode
through 220 ohm or
greater.
7
3V3 3.3 V power 3V3 3.3V power, connect to
LED anodes.
8, 10
USB Device Port
The PW2050 embedded device server has one USB 2.0 device port interface for connection to
an upstream USB device. The port consists of a differential pair, signals DDP and DDM.
These signals should be routed as a 90 ohm differential pair on a signal layer next to the signal
ground plane. The use of vias should be minimized on these signals. The USB signals can be
connected to a USB Mini Type B USB port or directly to an IC with a USB host port. If
connecting to an external port that is user accessible it is recommended to add a TVS diode
array to the signal nets for ESD protection. The ESD array shown in the figure is of type
SEMTECH RCIamp0502A. This device features through pin routing to minimize trace
impedance changes and simplify routing. The footprint for the TVS array can be added to the
PCB and the part can be depopulated if it is not needed. It is recommended that the power
drawn off the USB Mini Type B connector be limited to less than 500mA per USB requirements.
If the USB device port is unused the DDP and DDM pins may be left unconnected.
Table 2-9 USB Device Port Signals
Pin Name Description
Module
Pins
Signal
Requirement
Mini Type B
USB Device
connector pin
USB+/DDP
USB Device Port
Positive pin
18
Route as 90 ohm
differential pair with
DDM signal
3
USB-/DDM
USB Device Port
Negative pin
19
Route as 90 ohm
differential pair with
DDP signal
2
5V
5V power from USB
cable
Current limit to 500
mA per port
1
Ground Signal Ground Ground Ground plane 5