ICS1893AGILF View Datasheet(PDF) - Integrated Circuit Systems
Part Name
Description
MFG CO.
'ICS1893AGILF' PDF : 135 Pages View PDF
ICS1893AG Data Sheet - Preliminary
Chapter 6 Interface Overviews
6.3.1 Twisted-Pair Transmitter Interface
The twisted-pair transmitter driver uses an H-bridge configuration. ICS suggests any of for the H-bridge:
• Halo TG22S012ND transformer
• Transpower HB617-LP transformer
• Pulse 68517 transformer which can be turned around to move the choke windings to the RJ-45 side.
Figure 6-1 shows the design for the ICS1893AG twisted-pair transmitter interface.
• Two 61.9Ω 1% resistors are in series, with a 120-nH 5% inductor between them. These components
form a network that connects across both the transformer and the ICS1893AG TP_TXP and TP_TXN
pins.
• The ICS1893AG transmitter output H drive configuration supplies power to the transformer. (No VDD
connection is required.)
• The ICS1893AG TP_CT pin is connected directly to the transformer transmit center tap connection and
is bypassed to ground with a 100-pF capacitor.
Note:
1. If the transmit transformer has a choke, it may be put on the chip side, the RJ-45 side, or both.
2. Keep all TX traces as short as possible.
3. When making board traces, 50Ω-characteristic impedance is desirable.
Figure 6-1. ICS1893AG Transmit Twisted Pair
System Ground Plane Chassis Ground Plane
TP_TXP 13
ICS1893AG
61.9Ω 1%
120 nH
1:1
Center
Tap
61.9Ω 1%
TP_TXN 14
TP_CT 11
Ideally, for these traces Zo = 50Ω.
100 pF
Separate Ground Plane
To RJ-45
75Ω
0.1 µF
ICS1893AG, Rev A 04/14/05
Copyright © 2005, Integrated Circuit Systems, Inc.
All rights reserved.
26
April, 2005
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