ICS1893 Datasheet, PDF (124/152 Pages) Integrated Circuit Systems – 3.3-V 10Base-T/100Base-TX Integrated PHYceiver™

ICS1893 Data Sheet - Release
Chapter 10 DC and AC Operating Conditions
10.3 Recommended Component Values
Table 10-3. Recommended Component Values for ICS1893
Parameter
Minimum
Typical
Oscillator Frequency
–
25
10TCSR Resistor Value
–
2.00k
100TCSR Resistor Value
–
See Figure 10-1
LED Resistor Value
510
1k
Maximum
–
–
–
10k
Tolerance
± 50 ppm †
1%
1%
–
Units
MHz
Ω
Ω
Ω
† There are two IEEE Std 802.3 requirements that drive the tolerance for the frequency of the oscillator.
• Clause 22.2.2.1 requires the MII TX_CLK to have an accuracy of ± 100 ppm.
• Clause 24.2.3.4 is more stringent. It requires the code-bit timer to have an accuracy of 0.005% (that is, ±50 ppm).
Note: Although the 10TCSR and 100TCSR pins do not need to be bypassed, include placeholders for
bypass capacitors on a printed circuit board that uses the ICS1893.
Figure 10-1. ICS1893 10TCSR and 100TCSR
VDD
7
VDD
ICS1893
10TCSR
9
12.1 KΩ 1%
100TCSR
10
10TCSR
2.0KΩ 1%
100TCSR
1.54KΩ 1%
ICS1893 Rev C 6/6/00
Leave place holder but do not install bypass capacitors.
Copyright © 2000, Integrated Circuit Systems, Inc.
All rights reserved.
124
June, 2000