1893BFLFT IDT, 1893BFLFT Datasheet - Page 41

• Manufacturer Part Number: 1893BFLFT
• Description: Ethernet ICs 3.3V 10/100 BASE TX INTEGRATED PHYCEIVER
• Manufacturer: IDT

Specifications of 1893BFLFT

• Rohs: yes
• Part # Aliases: ICS1893BFLFT

6.4.6 100Base-TX Operation: Twisted-Pair Receiver
6.4.7 100Base-TX Operation: Isolation Transformer
6.5 Functional Block: 10Base-T Operations
6.5.1 10Base-T Operation: Manchester Encoder/Decoder
ICS1893BF, Rev. F, 5/13/10
The ICS1893BF uses the same Twisted-Pair Receive pins (TP_RXP and TP_RXN) for both 10Base-T and
100Base-TX operations. The internal twisted-pair receiver modules interface with the medium through an
isolation transformer. The 100Base-TX receiver module accepts and processes a differential three-level
100Base-TX (that is, MLT-3 encoded) signal from the isolation transformer. (In contrast, the 10Base-T
receiver module accepts and processes a differential two-level, Manchester- encoded, 10Base-T signal
from the isolation transformer).
Note:
1. In reference to the ICS1893BF, the term ‘Twisted-Pair Receiver’ refers to the set of Twisted-Pair
2. For information on the 10Base-T Twisted-Pair Receiver, see
The ICS1893BF interfaces with a medium through isolation transformers. The PHY requires two isolation
transformers: one for its Twisted-Pair Transmitter and the other for its Twisted-Pair Receiver. These
isolation transformers provide both physical isolation as well as the means for coupling a signal between
the ICS1893BF and the medium for both 10Base-T and 100Base-TX operations.
Note:
When configured for 10Base-T mode, the ICS1893BF MAC Interface is configured to provide 10M MII
(Media Independent Interface). The Twisted-Pair Interface is automatically configured to provide a
two-level, Manchester-encoded signal at the voltage levels specified in the ISO/IEC standard. (For more
information on the Twisted-Pair Interface, see
The 10Base-T and 100Base-TX operations differ as follows. 10Base-T operations are fundamentally
simpler than 100Base-TX operations. The data rate is slower, requiring less encoding than 100Base-TX
operations. In addition, the bandwidth requirements (and therefore the line attenuation issues) are not as
severe as with 100-MHz operations. Consequently, when an ICS1893BF is set for 10Base-T operations, it
requires fewer internal circuits in contrast to 100Base-TX operations. (For an overview of 10Base-T
operations, see
During data transmission the ICS1893BF acquires data from its MAC Interface in 4-bit nibbles. The
ICS1893BF converts this data into a Manchester-encoded signal for presentation to its MDI, as required by
the ISO/IEC specification.
In a Manchester-encoded signal, all logic:
•
•
Ones are:
Zeros are:
– Positive during the first half of the bit period
– Negative during the second half of the bit period
– Negative during the first half of the bit period
– Positive during the second half of the bit period
Receive output pins (TP_RXP and TP_RXN).
Twisted-Pair
ICS1893BF Data Sheet Rev. F - Release
For information on isolation transformers (also referred to as magnetic modules), see
“Twisted-Pair
Section 4.6, “10Base-T
Receiver”.
Interface”.
Operations”.).
Copyright © 2009, IDT, Inc.
All rights reserved.
Section 5.3, “Twisted-Pair
41
Section 6.5.12, “10Base-T Operation:
Interface”.)
Chapter 6 Functional Blocks
Section 5.3,
May, 2010